claude-code-20260909T170702Z / documentation capture

What this read moved

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communications-kit Changed · +4 / -2 lines

from line 207

207207mid-session. *Sonnet* is the workhorse default for everyday feature work,

208208bugs, tests, and reviews. Reach for *Opus* on large refactors, gnarly

209209debugging, or anything high-stakes. Drop to *Haiku* for quick questions,

210formatting, and mechanical edits where speed wins. *Fable* is the most

210formatting, and mechanical edits where speed wins.

211

212*Fable* is the most

211213capable model for your hardest, longest-running tasks; it is not the

212214default, so select it with `/model fable`, and note that cybersecurity and

213215biology content falls back to Opus automatically. Opus 5 runs its own

from line 224

222224

223225| Model | Best for |

224226| ------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |

225| Fable | The hardest, longest-running tasks. Opt-in only: select it with `/model fable`. Cybersecurity or biology content [falls back to Opus](/docs/en/model-config#automatic-model-fallback) |

227| Fable | The hardest, longest-running tasks. Opt-in only: select it with `/model fable`. Cybersecurity or biology content triggers [automatic model fallback to Opus](/docs/en/model-config#automatic-model-fallback) |

226228| Opus | Large-scale refactors, complex debugging, architecture decisions, high-stakes changes. On Opus 5, cybersecurity or biology content triggers [automatic model fallback or a refusal](/docs/en/model-config#automatic-model-fallback) |

227229| Sonnet | Everyday feature work, bug fixes, tests, documentation, code review. Recommended default. |

228230| Haiku | Quick questions, formatting, mechanical edits, rapid iteration |

costs Changed · +5 / -1 lines

from line 304

304304

305305### Adjust extended thinking

306306

307Extended thinking is enabled by default because it significantly improves performance on complex planning and reasoning tasks. Thinking tokens are billed as output tokens, and the default budget can be tens of thousands of tokens per request depending on the model. For simpler tasks where deep reasoning isn't needed, you can reduce costs by lowering the [effort level](/docs/en/model-config#adjust-effort-level) with `/effort` or in `/model`, disabling thinking in `/config`, or, on models with a [fixed thinking budget](/docs/en/model-config#adaptive-reasoning-and-fixed-thinking-budgets), lowering the budget by setting the `MAX_THINKING_TOKENS` [environment variable](/docs/en/env-vars), for example `MAX_THINKING_TOKENS=8000`. Adaptive-reasoning models ignore nonzero budgets, so use effort levels there instead. Disabling thinking is not available on Fable models, which always use extended thinking.

308

309For simpler tasks where deep reasoning isn't needed, you can reduce costs by lowering the [effort level](/docs/en/model-config#adjust-effort-level) with `/effort` or in `/model`, or by disabling thinking in `/config`. You can't turn off thinking on Fable models, which always use extended thinking.

310

311On models with a [fixed thinking budget](/docs/en/model-config#adaptive-reasoning-and-fixed-thinking-budgets), you can also lower the budget by setting the `MAX_THINKING_TOKENS` [environment variable](/docs/en/env-vars), for example `MAX_THINKING_TOKENS=8000`. Adaptive-reasoning models ignore nonzero budgets, so use effort levels there instead.

308312

309313### Delegate verbose operations to subagents

310314

errors Changed · +20 / -1 lines

### Model switch was blocked by a PreModelSwitch hook

This page is larger than the 256 KiB this site keeps, so one side of the diff below stops where the stored text does.

from line 115

115115| `Claude Opus is not available with the Claude Pro plan` | [Request errors](#claude-opus-is-not-available-with-the-claude-pro-plan) |

116116| `Claude Code ... does not support this model; version ... or newer is required` | [Request errors](#claude-code-does-not-support-this-model) |

117117| `Model ... is restricted by your organization's settings` | [Request errors](#model-is-restricted-by-your-organizations-settings) |

118| `Model switch ... blocked by a PreModelSwitch hook` | [Request errors](#model-switch-was-blocked-by-a-premodelswitch-hook) |

118119| `thinking.type.enabled is not supported for this model` | [Request errors](#thinking-type-enabled-is-not-supported-for-this-model) |

119120| `Effort '<level>' isn't available with thinking turned off on this model` | [Request errors](#effort-isnt-available-with-thinking-turned-off) |

120121| `effort '<level>' is not supported when thinking is disabled` | [Request errors](#effort-isnt-available-with-thinking-turned-off) |

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551552Fable 5.1 now uses usage credits · the prompt to confirm went unanswered — nothing was sent · answer it where this session is running, or /model to change

552553```

553554

554The messages name the session's Fable model, so on Fable 5 they read `continuing on Fable 5` and `Fable 5 now uses usage credits`. Before v2.1.255, the first message began `Fable 5 limit reached`.

555The messages name the session's Fable model, so on Fable 5 they read `continuing on Fable 5` and `Fable 5 now uses usage credits`. Before v2.1.257, the first message began `Fable 5 limit reached`.

555556

556557This happens in [Remote Control](/docs/en/remote-control) sessions, [background sessions](/docs/en/agent-view), and [agent team](/docs/en/agent-teams) teammate sessions. Claude Code shows the consent prompt only in the session's own interactive view: the terminal where it runs, or, for a background session, the [agents view](/docs/en/agent-view) once you attach. A Remote Control client can't display it. Claude Code closes the prompt at the [`dialogExpiry`](/docs/en/settings-reference#dialogexpiry) deadline, five minutes by default, or as soon as a new prompt arrives while nobody has typed at that terminal, such as a prompt sent from a Remote Control client. Typing at the terminal where the session runs cancels the deadline, and Claude Code waits for your answer. In a background session's attached view, typing doesn't cancel the deadline, and a new prompt still closes the consent prompt, so answer before either happens. Claude Code sends nothing and keeps your model, so when you send your next prompt, Claude Code shows the consent prompt again.

557558

from line 1710

17091710* If the restricted model was set in `--model`, `ANTHROPIC_MODEL`, the `model` field of a settings file, or the `model` frontmatter of a [subagent](/docs/en/sub-agents#choose-a-model), skill, or command, remove or update that value so the notice doesn't recur

17101711* If you need access to the restricted model, ask your organization admin to enable it. See [Organization model restrictions](/docs/en/model-config#organization-model-restrictions).

17111712

1713### Model switch was blocked by a PreModelSwitch hook

1714

1715A [PreModelSwitch hook](/docs/en/hooks#premodelswitch) didn't approve the model switch you or a client requested, so the session keeps its current model. When the switch came from an [Agent SDK](/docs/en/agent-sdk/overview) host or [Remote Control](/docs/en/remote-control) rather than a command you typed, the message reads `Model switch blocked by a PreModelSwitch hook` without naming the target model.

1716

1717```text theme={null}

1718Model switch to Opus 4.6 was blocked by a PreModelSwitch hook: Opus 4.6 is retired for this project. Use a newer model.

1719```

1720

1721The reason after the colon says what refused the switch:

1722

1723* **A reason a hook wrote**: a PreModelSwitch hook supplied that reason when it [denied the switch or asked for confirmation](/docs/en/hooks#premodelswitch-decision-control). Address what it asks, or pick a model your hooks allow.

1724* **`PreModelSwitch hook <name> did not respond before its timeout`**: a hook that doesn't answer before its [timeout](/docs/en/hooks#timeouts) blocks the switch. Fix the hanging command or raise that hook's `timeout`, then switch again.

1725* **`confirmation required, and this session cannot ask`**: a hook answered `ask` without a reason, and a control request has no way to show the confirmation prompt. A `/model` command in a [`-p` run](/docs/en/headless) reports the same condition with `(run /model interactively to confirm)` after the reason. Make the switch from an interactive session, or change the hook's decision for this model.

1726* **`so organization-managed PreModelSwitch hooks could not be checked`**: Claude Code couldn't tell which PreModelSwitch hooks your organization's [managed plugins](/docs/en/settings-reference#enabledplugins) deliver, for example because a managed plugin failed to load. One of those hooks might block the switch, so Claude Code refuses rather than apply the switch unchecked. The start of the reason names what failed. Claude Code re-checks on every switch attempt, so a failure that has since cleared stops blocking; if it keeps failing, run `claude --debug` and switch again to capture the details, then fix the plugin or ask your admin to fix it.

1727* **`a PreModelSwitch hook failed before answering`** or **`PreModelSwitch hooks were cancelled (the control stream closed) before answering`**: the hook run ended without a verdict, and Claude Code doesn't treat that as approval. Run `claude --debug` to see what failed, then switch again.

1728

1729Before v2.1.260, the managed-plugin refusal read `plugin hooks could not be loaded, so PreModelSwitch hooks could not be checked; see the debug log`. Claude Code retried the plugin load once and then refused later switches in the session, even when your organization managed no plugins. Restart the session to run the plugin load again on those versions.

1730

17121731### thinking.type.enabled is not supported for this model

17131732

17141733Your Claude Code version is older than the minimum for the selected model. The CLI sent a thinking configuration the model no longer accepts.

from line 2328

23092328**What to do:**

23102329

23112330* Run `claude --resume <session-id>` with the session ID from the message to retry

2312* If the retry fails again, run `claude` to start a new session

2313

2314### No conversation found with the session ID

2315

2316You passed a session ID to `claude --resume <session-id>` and no saved transcript matched it:

2317

2318```text theme={null}

2319No conversation found with session ID: <session-id>

2320```

2321

2322Claude Code exits with code 1 after showing the message. Claude Code [searches the current project first, then every other project on this machine](/docs/en/sessions#resume-a-session) for the ID. Before v2.1.223, the lookup stopped at the current project directory and its git worktrees, so resume from the directory the session last worked in.

2323

2324Common causes:

2325

2326* **Mistyped ID**: for a non-interactive run, the ID is the `session_id` field of the [`--output-format json` output](/docs/en/headless#get-structured-output)

2327* **Deleted transcript**: Claude Code removes transcripts after the [retention period](/docs/en/sessions#where-transcripts-are-stored), 30 days by default, following the [retention sweep rules](/docs/en/claude-directory#cleaned-up-automatically)

2328* **Different machine**: Claude Code stores transcripts locally, so resume the session on the machine where it ran

2329* **Duplicate copies**: if you copied a project directory under `~/.claude/projects` so two transcripts carry the same ID, Claude Code reports this message rather than resume one copy arbitrarily

2330

2331**What to do:**

2332

2333* For an interactive session, open the [session picker](/docs/en/sessions#use-the-session-picker) with `claude --resume` and press `Ctrl+A` to widen it to every project on this machine, then select the session

2334* Sessions created with `claude -p` or the [Agent SDK](/docs/en/agent-sdk/overview) don't appear in the picker, so re-check the ID against the `session_id` your original run printed

2335

2336### Cannot switch renderers in this session

2337

2338When you switch renderers, Claude Code restarts its process. You ran [`/tui`](/docs/en/fullscreen#enable-fullscreen-rendering) in a session Claude Code declines to restart, so it doesn't switch and saves nothing. Which message you see tells you the cause:

2339

2340* `Cannot switch renderers while work is running in the background`: you have background work running that a restart would abandon, such as a background shell or a subagent. Wait for the work to finish or stop it with [`/tasks`](/docs/en/commands), then run `/tui fullscreen` or `/tui default` again

2341* `Cannot switch renderers in this session`: the session has restrictions Claude Code can't pass to the restarted process. Before v2.1.234, Claude Code restarted anyway and the relaunched session ran without them

2342

2343In the restrictions message, the part in parentheses names the restrictions Claude Code found:

2344

2345```text theme={null}

2346Cannot switch renderers in this session — it has restrictions a restart can't carry over (permission rules set for this session only). Nothing was changed. Running /tui fullscreen in a session started without them switches every later session too.

2347```

2348

2349Each reason the message can show in parentheses:

2350

2351* `launch flags: a custom system prompt, a tool allowlist, or restricted settings`: you started the session with a flag Claude Code doesn't pass back to the restarted process. These flags include [`--sys

2331* If the retry fails again, run `claude` to start

interactive-mode Changed · +14 / -11 lines

from line 291

291291* Background tasks are automatically cleaned up when Claude Code exits. On macOS and Linux, when you stop a background task from [`/tasks`](/docs/en/commands) or Claude Code stops it at exit, processes that detached from the task's shell, such as ones started under `setsid` or `timeout`, stop too

292292* If you background the session instead of exiting it, your background tasks keep running in the background session. See [background a running session](/docs/en/agent-view#from-inside-a-session)

293293* Background tasks are automatically terminated if output exceeds 5GB, with a note in stderr explaining why

294* On macOS and Linux, Claude Code terminates running background tasks when the operating system signals memory pressure, provided the session has been idle for at least 30 minutes and no turn or subagent is running. Set [`CLAUDE_CODE_DISABLE_BG_SHELL_PRESSURE_REAP`](/docs/en/env-vars) to `1` to turn this off. Requires Claude Code v2.1.193 or later. Background commands owned by a [subagent](/docs/en/sub-agents) are instead terminated after 60 minutes, configurable in milliseconds with [`CLAUDE_SUBAGENT_BG_SHELL_MAX_MS`](/docs/en/env-vars). A command owned by a subagent running in the foreground also ends when that subagent gives its final response; see [Background commands](/docs/en/tools-reference#background-commands) in the tools reference. Before v2.1.218, neither the memory-pressure reap nor the 60-minute limit covered commands moved to the background with `Ctrl+B`

295* Background commands owned by a [subagent](/docs/en/sub-agents) have no time limit, except that a command owned by a subagent running in the foreground ends when that subagent gives its final response; see [Background commands](/docs/en/tools-reference#background-commands) in the tools reference. Before v2.1.218, neither the memory-pressure reap nor the former 60-minute limit on subagent commands covered commands moved to the background with `Ctrl+B`

295296

296297To disable all background task functionality, set the `CLAUDE_CODE_DISABLE_BACKGROUND_TASKS` environment variable to `1`. See [Environment variables](/docs/en/env-vars) for details.

297298

from line 563

562563

563564Your five newest earlier side questions appear as a dimmed list above the current answer, with a count of any older ones. They stay out of the conversation history.

564565

565To return to the overlay after dismissing it, run `/btw` with no question. The overlay reopens on your most recent exchange. Press `Left` to step back through earlier answers. Before v2.1.212, `/btw` without a question printed a usage message instead.

566To return to the overlay after dismissing it, run `/btw` with no question. The overlay reopens on your most recent exchange. Before v2.1.212, `/btw` without a question printed a usage message instead.

566567

567568Once the answer appears, the overlay accepts these keys.

568569

569| Key | Action |

570| :------------------------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

571| `Space`, `Enter`, `Escape` | Dismiss the answer and return to the prompt |

572| `Up` / `Down` | Scroll the answer |

573| `Left` / `Right` | Step between this answer and your earlier `/btw` answers. `Left` moves to older answers and `Right` returns toward the current one. Requires Claude Code v2.1.187 or later |

574| `c` | Copy the answer to your clipboard as raw Markdown. Use this instead of mouse selection, which captures the hard-wrapped terminal rendering rather than the source text |

575| `f` | Start a [forked subagent](/docs/en/sub-agents#fork-the-current-conversation) that inherits the parent conversation plus this question and answer, so it can continue with full tool access. You stay in the current session and find the fork in the [panel below your prompt](/docs/en/sub-agents#observe-and-steer-running-forks). Available in local sessions only |

576| `x` | Clear the list of earlier `/btw` exchanges shown above the current answer |

570| Key | Action |

571| :--------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |

572| `Space`, `Enter`, `Escape` | Dismiss the answer and return to the prompt |

573| `Up` / `Down` | Scroll the answer |

574| `Shift+Left` / `Shift+Right` | Step between this answer and your earlier `/btw` answers. `Shift+Left` moves to older answers and `Shift+Right` returns toward the current one. `[` and `]` do the same, for terminals that don't report `Shift` with arrow keys. `Tab` / `Shift+Tab` cycle through the same answers. Requires Claude Code v2.1.257 or later. Between v2.1.187 and v2.1.256, the keys were plain `Left` / `Right` |

575| `c` | Copy the answer to your clipboard as raw Markdown. Use this instead of mouse selection, which captures the hard-wrapped terminal rendering rather than the source text |

576| `f` | Start a [forked subagent](/docs/en/sub-agents#fork-the-current-conversation) that inherits the parent conversation plus this question and answer, so it can continue with full tool access. You stay in the current session and find the fork in the [panel below your prompt](/docs/en/sub-agents#observe-and-steer-running-forks). Available in local sessions only |

577| `x` | Clear the list of earlier `/btw` exchanges shown above the current answer |

577578

579In an attached [background session](/docs/en/agent-view#attach-to-a-session), `Left` detaches and returns you to agent view, even while the answer is still arriving. The side question keeps running while you're away. The next time you attach to the session, the overlay reopens with the side question, or with its answer. Before v2.1.257, `Left` didn't detach there.

580

578581`/btw` sees your full conversation but has no tools. A [subagent](/docs/en/sub-agents) has tools and starts from the prompt it receives, or, for a [fork](/docs/en/sub-agents#fork-the-current-conversation), from a copy of this conversation. Use `/btw` to ask about what Claude already knows from this session; use a subagent to go find out something new.

579582

580583## Task list

from line 689

686689

687690The badge disappears once the merge request merges or closes.

688691

689It refreshes as soon as a `glab mr create` or `git push` succeeds in the session.

692It refreshes as soon as a `git push`, or a `glab mr` command that changes the merge request, such as `glab mr create` or `glab mr merge`, succeeds in the session.

690693

691694To get the badge, you need:

692695

managed-mcp Changed · +5 / -5 lines

from line 92

9292When a session receives servers through `--mcp-config` while `managed-mcp.json` is deployed, what the user sees differs between a workstation and a cloud session:

9393

9494* On a workstation, Claude Code exits at startup with `You cannot dynamically configure MCP servers when an enterprise MCP config is present`.

95* In [cloud sessions](/docs/en/claude-code-on-the-web) on a host where the file is deployed, such as a [self-hosted runner](/docs/en/self-hosted-environments-configuration#mcp-servers), Claude Code starts with the managed servers only and skips the claude.ai connectors and other servers the cloud host delivers through `--mcp-config`. Nothing in the session tells the user which servers were left out. Claude Code names them in a warning on its stderr, which a self-hosted runner records at the `debug` log level. Before v2.1.229, these sessions exited with the same error a workstation shows.

9696

9797If a user passes `--strict-mcp-config`, Claude Code exits at startup on a workstation and in a cloud session alike, because that flag asks to replace the managed set.

9898

from line 172

172172* No value contains a `${VAR}` reference. Claude Code doesn't expand environment variables in these entries, so write literal values.

173173* The server name contains only letters, numbers, hyphens, and underscores, and no key or value contains control or invisible formatting characters.

174174

175Claude Desktop has a managed setting with the same name whose value is an array of a different entry shape, so don't copy one into the other. Claude Code doesn't accept the array form and records a notice instead of loading it. Write the server name as the object key and use `type` rather than `transport`.

176176

177177A Claude apps gateway runs the same checks when it boots; see [MCP servers in a policy](/docs/en/claude-apps-gateway-config#mcp-servers-in-a-policy).

178178

from line 187

187187

188188When you haven't also deployed `managed-mcp.json`, the per-run flags keep their meaning:

189189

190* A server a user passes with `--mcp-config` under the same name replaces the provided one for that run and is checked against `allowedMcpServers` like any server the user adds.

190* A server a user passes with `--mcp-config` under the same name replaces the provided one for that run and is checked against `allowedMcpServers`.

191191* `--strict-mcp-config` leaves provided servers out along with every other configured server.

192192

193193With `managed-mcp.json` deployed, both flags behave as [Exclusive control with managed-mcp.json](#exclusive-control-with-managed-mcp-json) describes.

from line 200

200200* When you haven't also deployed `managed-mcp.json`, an entry a user adds under the same name is saved but not used while yours is present.

201201* Users can still turn a provided server off for themselves in [`/mcp`](/docs/en/mcp#disable-a-server-without-removing-it), which lists provided servers under **Managed MCPs**.

202202

203`claude mcp get` and `/mcp` show a provided server's URL as its host only, for example `https://mcp.example.com/…`, and `claude mcp get` shows its header names without their values. That display keeps the values off screens and logs; the settings document on the user's machine still holds them.

203`claude mcp get` and `/mcp` show a provided server's URL as its host only, for example `https://mcp.example.com/…`, and `claude mcp get` shows its header names without their values.

204204

205205### Where `managedMcpServers` applies

206206

207207Claude Code reads `managedMcpServers` from the managed source it selects under [How Claude Code combines managed sources](/docs/en/managed-settings#how-claude-code-combines-managed-sources). When that source sets [`managedSourcesBehavior`](/docs/en/settings-reference#managedsourcesbehavior) to `"merge"`, Claude Code provides the servers from every admin source instead, and when two sources define the same name, the higher-ranked source's entry applies whole. It never reads the key from the user-writable HKCU registry, from [parent settings an embedding host supplies](/docs/en/managed-settings#parent-settings-from-embedding-hosts), or from user, project, or local settings files, where it drops the key with a warning.

208208

209Claude Code doesn't read the key in the Claude Desktop app's Code tab on a third-party deployment or in the app's Cowork sessions, because Claude Desktop supplies and locks those sessions' MCP servers itself; on a third-party deployment it does so from its own `managedMcpServers` setting. `/status` and `claude doctor` say so when your managed settings carry the key there. The Code tab of a Claude Desktop signed in to claude.ai reads the key as the terminal does.

210210

211211### When provided servers connect

212212

model-config Changed · +51 / -28 lines

from line 26

2626| Model alias | Behavior |

2727| ---------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

2828| **`default`** | Special value that clears any model override and reverts to the [runtime default for your account](#default-model-setting). Not itself a model alias |

29| **`best`** | Uses the latest Fable model where it's available to you, otherwise the same model as `opus` |

30| **`fable`** | Uses the latest Fable model for your hardest and longest-running tasks |

29| **`best`** | Uses the model the [`fable` alias resolves to](#fable-alias-resolution) where Fable is available to you, otherwise the same model as `opus` |

30| **`fable`** | Uses the [Fable model for your provider](#fable-alias-resolution) for your hardest and longest-running tasks |

3131| **`sonnet`** | Uses the latest Sonnet model for daily coding tasks |

3232| **`opus`** | Uses the latest Opus model for complex reasoning tasks |

3333| **`haiku`** | Uses the fast and efficient Haiku model for simple tasks |

from line 44

4444| Amazon Bedrock, Google Cloud's Agent Platform | Opus 5 | Sonnet 4.5 |

4545| Microsoft Foundry | Opus 4.6 | Sonnet 4.5 |

4646

47Unless you set `ANTHROPIC_DEFAULT_FABLE_MODEL`, the `fable` alias resolves to Fable 5.1. Before v2.1.255, it resolved to Fable 5.

47<span id="fable-alias-resolution" />

4848

49Unless you set `ANTHROPIC_DEFAULT_FABLE_MODEL`, the `fable` alias resolves to Fable 5.1, except in [Claude apps gateway](/docs/en/claude-apps-gateway) sessions, where `fable` and `best` resolve to Fable 5. Before v2.1.257, `fable` resolved to Fable 5 on every provider.

51A gateway that isn't configured to serve `claude-fable-5-1` rejects requests for that model. To use Fable 5.1 through a gateway that serves it, select it with `/model claude-fable-5-1`.

4953Where an alias resolves to an older model, newer models are available by selecting the full model name explicitly or setting `ANTHROPIC_DEFAULT_OPUS_MODEL` or `ANTHROPIC_DEFAULT_SONNET_MODEL`.

5054

5155Before v2.1.219, `opus` resolved to Opus 4.8 on the Anthropic API from v2.1.154, and on Claude Platform on AWS, Amazon Bedrock, and Google Cloud's Agent Platform from v2.1.207. Before v2.1.207, `opus` resolved to Opus 4.7 on Claude Platform on AWS and to Opus 4.6 on Amazon Bedrock and Google Cloud's Agent Platform.

from line 66

6266

6367Neither Fable model is the account-type default on any plan or provider. Select one explicitly:

6468

65* **Fable 5.1**: run `/model fable`, or launch with `claude --model fable`.

69* **Fable 5.1**: run `/model fable`, or launch with `claude --model fable`. In [Claude apps gateway](/docs/en/claude-apps-gateway) sessions, where the alias resolves to Fable 5, run `/model claude-fable-5-1` instead.

6670* **Fable 5**: select it by model ID. On the Anthropic API, run `/model claude-fable-5` or launch with `claude --model claude-fable-5`. On other providers, use your provider's Fable 5 model ID or [pin it](#pin-models-for-third-party-deployments) with `ANTHROPIC_DEFAULT_FABLE_MODEL`.

6771

68If your user settings hold `claude-fable-5` or `claude-fable-5[1m]` as the model, for example because you selected Fable in the `/model` picker before v2.1.255, and you connect to the Anthropic API directly, Claude Code changes that saved value to the `fable` or `fable[1m]` alias the first time you run v2.1.255 or later, and the startup model line shows `(auto-updated)` once. A `claude-fable-5` value in project, local, or managed settings is left as it is.

72If you connect to the Anthropic API directly and your user settings hold `claude-fable-5` or `claude-fable-5[1m]` as the model, for example because you selected Fable in the `/model` picker before v2.1.257, Claude Code changes that saved value to the `fable` or `fable[1m]` alias the first time you run v2.1.257 or later. The startup model line shows `(auto-updated)` once. A `claude-fable-5` value in project, local, or managed settings stays as it is.

6973

7074Requests that a Fable model's safety classifiers flag, most often in cybersecurity and biology domains, trigger [automatic model fallback](#automatic-model-fallback).

7175

from line 81

7781* **Size up larger tasks**: give it work you would normally break into pieces. It holds long sessions without losing the thread.

7882

7983<Note>

80 Fable 5.1 requires Claude Code v2.1.255 or later. If a request for it from an older version fails, see [Claude Code does not support this model](/docs/en/errors#claude-code-does-not-support-this-model). Fable 5 requires v2.1.170 or later. Run `claude update` to upgrade. For availability under zero data retention, see [Model availability under ZDR](/docs/en/zero-data-retention#model-availability-under-zdr).

84 Fable 5.1 requires Claude Code v2.1.257 or later. If a request for it from an older version fails, see [Claude Code does not support this model](/docs/en/errors#claude-code-does-not-support-this-model). Fable 5 requires v2.1.170 or later. Run `claude update` to upgrade. For availability under zero data retention, see [Model availability under ZDR](/docs/en/zero-data-retention#model-availability-under-zdr).

8185</Note>

8286

8387On the Anthropic API, the `/model` picker lists a Fable model only after the server reports it available for your organization. When you type `/model fable` or a Fable model ID, Claude Code checks availability with the server directly, so a typed selection can succeed even when the picker doesn't list the entry.

from line 136

132136

133137When the active model at startup comes from project or managed settings rather than your own selection, the startup header shows which settings file set it. Run `/model` to override; the project or managed setting reapplies on the next launch. On platforms that embed Claude Code and set [`CLAUDE_CODE_PROVIDER_MANAGED_BY_HOST`](/docs/en/env-vars), the host's model configuration takes precedence over managed model settings, while a managed `availableModels` allowlist stays in force unless the host supplies its own; [Exceptions to managed settings precedence](/docs/en/settings#exceptions-to-managed-settings-precedence) says which keys and variables the host overrides.

134138

135When a model switch is requested through the [Agent SDK](/docs/en/agent-sdk/overview) `setModel()` method or by an app such as the [Desktop app](/docs/en/desktop) that runs the Claude Code CLI for you, Claude Code checks that the string is one it recognizes before saving it. This check requires Claude Code v2.1.200 or later. On the Anthropic API, Claude Code recognizes:

139If you or your organization configure [PreModelSwitch hooks](/docs/en/hooks#premodelswitch), they run before a requested switch applies and can block it or ask you to confirm.

136140

141When Claude Code can't tell which PreModelSwitch hooks your organization's [managed plugins](/docs/en/settings-reference#enabledplugins) deliver, for example because a managed plugin failed to load, it refuses the switch rather than apply it unchecked, and it checks again on each new attempt. See [Model switch was blocked by a PreModelSwitch hook](/docs/en/errors#model-switch-was-blocked-by-a-premodelswitch-hook) for the message and recovery.

142

143When you switch models through the [Agent SDK](/docs/en/agent-sdk/overview) `setModel()` method or from a device connected through [Remote Control](/docs/en/remote-control), or an app such as the [Desktop app](/docs/en/desktop) that runs the Claude Code CLI switches for you, Claude Code checks that the string is one it recognizes before saving it. This check requires Claude Code v2.1.200 or later. Checking a Remote Control pick requires Claude Code v2.1.260 or later on your machine. On the Anthropic API, Claude Code recognizes:

144

137145* a model alias

138146* an entry from the `/model` picker

139147* any name that starts with `claude-`

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400408

401409When managed settings [enforce the allowlist for the Default model](#enforce-the-allowlist-for-the-default-model) and the account-type default is not in `availableModels`, `default` resolves to the enforced Default instead of the account-type default above. When both apply, the organization default replaces the account-type default first and enforcement then applies to it: an allowlisted organization default is kept, while one outside the list resolves to the enforced Default.

402410

403Fable models are not the account-type default on any plan or provider. Choosing one with `/model` saves it as the selected model in your user settings, so later sessions start on it. For the one-time change Claude Code makes to a saved Fable 5 selection in v2.1.255, see [Work with Fable](#work-with-fable).

411Fable models are not the account-type default on any plan or provider. Choosing one with `/model` saves it as the selected model in your user settings, so later sessions start on it. For the one-time change Claude Code makes to a saved Fable 5 selection in v2.1.257, see [Work with Fable](#work-with-fable).

404412

405413### `opusplan` model setting

406414

from line 525

517525With the [`ultracode`](/docs/en/settings-reference#ultracode) setting off, Claude Code resolves the session's effort level in this order, taking the first that applies:

518526

5195271. An explicit choice: the [`CLAUDE_CODE_EFFORT_LEVEL`](/docs/en/env-vars#variables) environment variable, launching with `--effort`, or `/effort` in the session ([a non-interactive `/effort` has narrower effect](#non-interactive-effort))

5202. The model's default effort, on Fable 5, Opus 4.8, or Opus 4.7: from the first time you run one of these models, Claude Code holds that model's default effort across sessions, even when your settings resolve a different level, until you change effort once, for example with an interactive `/effort`, the `/model` picker's effort slider, or `--effort` at launch. Opus 5 and Fable 5.1 have no such hold

5282. The model's default effort, on Fable 5, Opus 4.8, or Opus 4.7: from the first time you run one of these models, Claude Code holds that model's default effort across sessions, even when your settings resolve a different level. Opus 5 and Fable 5.1 have no such hold. Whether a level you set ends the hold depends on how you set it, for example:

529 * **Ends the hold**: confirming a level interactively, with `Enter` in the `/effort` slider or the `/model` picker or with a level typed after `/effort`, or picking a level from a connected device's [Remote Control](/docs/en/remote-control#what-connected-devices-see) effort control

530 * **Leaves the hold in place for later sessions**: `--effort` at launch, or `s` in the `/effort` slider or the `/model` picker

5215313. Your settings: the level you saved for the model or an [`effortLevel`](/docs/en/settings-reference#effortlevel) key, with the precedence between them and across settings files stated at [`modelSettings`](/docs/en/settings-reference#modelsettings)

5225324. The model's default effort: `high` on every model that supports effort, except that Opus 4.7 defaults to `xhigh` and, when your organization sets a default effort level for its [organization default model](#organization-default-model), that level is the default when you run that model

523533

524When you set `low`, `medium`, `high`, or `xhigh` in an interactive session on your machine, Claude Code saves the level and applies it in later sessions. It saves the level per model, under the [`modelSettings`](/docs/en/settings-reference#modelsettings) key in your user settings, so each model keeps its own saved level.

534When you set `low`, `medium`, `high`, or `xhigh` in an interactive session on your machine, you choose how long it lasts by how you confirm it:

525535

536* `Enter` in the `/effort` slider or the `/model` picker, or a level typed after `/effort`: save the level as your default and apply it in later sessions

537* `s` in the `/effort` slider or the `/model` picker: apply the level to this session only. Requires Claude Code v2.1.257 or later

538

539Claude Code saves the level per model, under the [`modelSettings`](/docs/en/settings-reference#modelsettings) key in your user settings, so each model keeps its own saved level.

540

526541`max` is the deepest reasoning level. Unless you set it through the `CLAUDE_CODE_EFFORT_LEVEL` environment variable, Claude Code applies `max` to the current session only.

527542

528543<Note>

from line 546

531546

532547<span id="non-interactive-effort" />

533548

534A level set with `/effort` in [non-interactive mode](/docs/en/headless), with the `-p` flag, applies to the current session only and isn't saved as your default. It also doesn't count as the one change that ends the model-default step above on Fable 5, Opus 4.8, or Opus 4.7: while that step is in effect, a non-interactive `/effort` reports `Not applied`, so pass `--effort` at launch instead.

549When you set a level with `/effort` in a [`-p` run](/docs/en/headless), Claude Code applies it to that session only and doesn't save it as your default. On Fable 5, Opus 4.8, and Opus 4.7, that level also neither ends the hold on the model's default effort nor overrides it for the session. While that hold is in effect, a non-interactive `/effort` reports `Not applied`, so pass `--effort` at launch instead.

535550

536551The `/effort` menu also offers `ultracode`. Ultracode is a Claude Code setting rather than a model effort level: it sends `xhigh` to the model and additionally has Claude orchestrate [dynamic workflows](/docs/en/workflows) for substantive tasks. For where it can be set persistently, see the [`ultracode`](/docs/en/settings-reference#ultracode) setting.

537552

from line 591

576591* **`--effort` flag**: pass a level name to set it for a single session when launching Claude Code

577592* **Environment variable**: set `CLAUDE_CODE_EFFORT_LEVEL` to a level name or `auto`

578593* **Settings**: set a per-model level in [`modelSettings`](/docs/en/settings-reference#modelsettings), or set [`effortLevel`](/docs/en/settings-reference#effortlevel) to `low`, `medium`, `high`, or `xhigh` as the default for models without one. `max` isn't accepted in either key, and `ultracode` has its own [`ultracode`](/docs/en/settings-reference#ultracode) key

579* **From a connected device**: in a [Remote Control](/docs/en/remote-control#what-connected-devices-see) session, pick a level from the effort control on your phone or in your browser. The level applies to the current session only. Requires Claude Code v2.1.234 or later

594* **From a connected device**: in a [Remote Control](/docs/en/remote-control#what-connected-devices-see) session, pick a level from the effort control on your phone or in your browser. The level applies to the current session only, though it also ends the [hold on the model's default effort](#adjust-effort-level). Requires Claude Code v2.1.234 or later

580595* **Skill and subagent frontmatter**: set `effort` in a [skill](/docs/en/skills#frontmatter-reference) or [subagent](/docs/en/sub-agents#supported-frontmatter-fields) markdown file to override the effort level when that skill or subagent runs

581596

582597Frontmatter effort applies when that skill or subagent is active, overriding the session level but not the environment variable.

from line 604

589604

590605Adaptive reasoning makes thinking optional on each step, so Claude can respond faster to routine prompts and reserve deeper thinking for steps that benefit from it. If you want Claude to think more or less often than the current level produces, you can say so directly in your prompt or in `CLAUDE.md`; the model responds to that guidance within its effort setting.

591606

592Fable 5.1, Fable 5, Sonnet 5, and Opus 4.7 and later always use adaptive reasoning. The fixed thinking budget mode and `CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING` do not apply to them.

607Fable models, Sonnet 5, and Opus 4.7 and later always use adaptive reasoning. The fixed thinking budget mode and `CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING` don't apply to them.

593608

594609On Opus 4.6 and Sonnet 4.6, you can set `CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING=1` to revert to the previous fixed thinking budget controlled by `MAX_THINKING_TOKENS`. See [environment variables](/docs/en/env-vars).

595610

from line 612

597612

598613Extended thinking is the reasoning Claude emits before responding. On models that support [adaptive reasoning](#adjust-effort-level), the effort level is the primary control for how much thinking happens; the settings below turn thinking on or off and control how it displays. With thinking turned off on the Anthropic API, Claude Code sends effort `high` instead of a higher level to models it knows [don't accept that combination](/docs/en/errors#effort-isnt-available-with-thinking-turned-off), such as Opus 5.

599614

600| Control | How to set it |

601| :-------------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

602| Toggle for the current session | Press `Option+T` on macOS or `Alt+T` on Windows and Linux |

603| Set the global default | Run `/config` and toggle thinking mode. Saved as `alwaysThinkingEnabled` in `~/.claude/settings.json` |

604| Disable through an environment variable | Set [`MAX_THINKING_TOKENS=0`](/docs/en/env-vars), which turns thinking off on the Anthropic API except on Fable 5.1 and Fable 5. On [third-party providers](/docs/en/third-party-integrations) this omits the `thinking` parameter instead, and adaptive-reasoning models may still think. Other values apply only with a [fixed thinking budget](#adaptive-reasoning-and-fixed-thinking-budgets) |

615| Control | How to set it |

616| :-------------------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

617| Toggle for the current session | Press `Option+T` on macOS or `Alt+T` on Windows and Linux |

618| Set the global default | Run `/config` and toggle thinking mode. Saved as `alwaysThinkingEnabled` in `~/.claude/settings.json` |

619| Disable through an environment variable | Set [`MAX_THINKING_TOKENS=0`](/docs/en/env-vars), which turns thinking off on the Anthropic API except on Fable models. On [third-party providers](/docs/en/third-party-integrations), Claude Code omits the `thinking` parameter instead, and adaptive-reasoning models may still think. Other values apply only with a [fixed thinking budget](#adaptive-reasoning-and-fixed-thinking-budgets) |

605620

606Thinking cannot be turned off on Fable 5.1 or Fable 5. The session toggle, `alwaysThinkingEnabled`, and `MAX_THINKING_TOKENS=0` have no effect there, and the model decides per step how much to think based on the effort level.

621You can't turn thinking off on Fable models. The session toggle, `alwaysThinkingEnabled`, and `MAX_THINKING_TOKENS=0` have no effect there, and a Fable model decides per step how much to think based on the effort level.

607622

608623Claude Code collapses thinking output by default. Press `Ctrl+O` to toggle verbose mode and see the reasoning as gray italic text. Interactive sessions on the Anthropic API receive redacted thinking blocks by default, so set `showThinkingSummaries: true` in [settings](/docs/en/settings) if you want the full summaries available when you expand. You are charged for all thinking tokens generated, even when collapsed or redacted.

609624

from line 696

681696* [Cloud sessions](/docs/en/claude-code-on-the-web) compact as the conversation approaches the model's limit

682697* Sonnet 4.6 and Opus 4.6 without [extended context](#extended-context) compact at the 200K boundary, and so do Opus 4.8 and Opus 5 when they run with a 200K context window, such as on Amazon Bedrock, Google Cloud's Agent Platform, and Microsoft Foundry

683698* When you set [`CLAUDE_CODE_DISABLE_1M_CONTEXT=1`](/docs/en/env-vars), models with a native 1M window, such as Sonnet 5 and the Fable models, compact at the 200K boundary

684* Sonnet 5 compacts at the [threshold for its configuration](#sonnet-5-context-window)

699* Models running with a native 1M window, such as Sonnet 5, the Fable models, and Opus 4.7 and later on the Anthropic API, compact before the window fills, at about 967K tokens by default. On Amazon Bedrock, Google Cloud's Agent Platform, and Microsoft Foundry, [Pin models for third-party deployments](#pin-models-for-third-party-deployments) says which models run with that window; for the configurations that budget Sonnet 5 at 200K instead, see [Sonnet 5 context window](#sonnet-5-context-window)

685700* Sessions on a model ID Claude Code doesn't recognize, such as an [LLM gateway](/docs/en/llm-gateway) alias, compact at the context window Claude Code assumes for the ID; see [Correct the window for a gateway or custom model ID](#correct-the-window-for-a-gateway-or-custom-model-id)

686701

687702### Correct the window for a gateway or custom model ID

688703

689On an [LLM gateway](/docs/en/llm-gateway) or other custom deployment, Claude Code can assume a context window for the model ID that differs from the model's real window, whether or not it resolves the ID to a Claude model. [`CLAUDE_CODE_MAX_CONTEXT_TOKENS`](/docs/en/env-vars) declares the window Claude Code should assume instead. How the variable applies depends on the ID. An unrecognized ID, an unrecognized `[1m]` ID, and an ID that starts with `claude-` or resolves to a Claude model are three separate cases:

704On an [LLM gateway](/docs/en/llm-gateway) or other custom deployment, Claude Code can assume a context window for the model ID that differs from the model's real window, whether or not it resolves the ID to a Claude model. Set [`CLAUDE_CODE_MAX_CONTEXT_TOKENS`](/docs/en/env-vars) to the window Claude Code should assume instead.

690705

691* If the ID doesn't start with `claude-` or contain `[1m]`, in any casing, and Claude Code can't resolve it to a Claude model, the variable applies directly and proactive compaction continues at the declared window.

692* If the ID doesn't start with `claude-` but contains `[1m]`, in any casing, and Claude Code can't resolve it to a Claude model, Claude Code assumes a 1M window for it and the variable doesn't apply on its own. To correct the window while keeping proactive compaction, also set [`CLAUDE_CODE_DISABLE_1M_CONTEXT=1`](/docs/en/env-vars). With a declared window above 200K, Claude Code then shows a [startup warning](/docs/en/errors#the-200k-limit-isnt-enforced) that the 200K limit isn't enforced. The warning is expected in this configuration.

693* If the ID starts with `claude-` in any casing or resolves to a Claude model, the variable takes effect only when [`DISABLE_COMPACT`](/docs/en/env-vars) is also set, which disables all compaction. For example, Claude Code resolves an ID that contains a Claude model name, such as `anthropic/claude-opus-4-8` or `us.anthropic.claude-…-v1:0`, to that model. This includes IDs that also contain `[1m]`: Claude Code resolves `claude-opus-4-8[1m]` to Opus 4.8 even with `CLAUDE_CODE_DISABLE_1M_CONTEXT` set.

706How the variable applies depends on the ID. Claude Code treats an ID as a provider or custom spelling when it doesn't start with `claude-`, in any casing, or when it carries a suffix that Claude Code strips when reading the ID, such as the `@YYYYMMDD` date used on Google Cloud's Agent Platform. Before v2.1.259, Claude Code didn't count a stripped suffix, so an unrecognized `claude-` ID with a date suffix was treated as a bare `claude-` name.

694707

708An unrecognized provider or custom spelling, the same spelling with `[1m]`, and every other ID are three separate cases:

709

710* If Claude Code can't resolve a provider or custom spelling to a model it recognizes and the ID doesn't contain `[1m]`, the variable applies directly and proactive compaction continues at the declared window.

711* If Claude Code can't resolve a provider or custom spelling to a model it recognizes and the ID contains `[1m]`, in any casing, Claude Code assumes a 1M window for it and the variable doesn't apply on its own. To correct the window while keeping proactive compaction, also set [`CLAUDE_CODE_DISABLE_1M_CONTEXT=1`](/docs/en/env-vars). With that variable set, Claude Code sizes the ID like the same spelling without `[1m]`, so `CLAUDE_CODE_MAX_CONTEXT_TOKENS` applies when it would apply to that untagged spelling.

712

713 With a declared window above 200K, Claude Code then shows a [startup warning](/docs/en/errors#the-200k-limit-isnt-enforced) that the 200K limit isn't enforced. The warning is expected in this configuration.

714* If the ID resolves to a model Claude Code recognizes, or the ID is a bare `claude-` name with no suffix for Claude Code to strip, in any casing, the variable takes effect only when you also set [`DISABLE_COMPACT`](/docs/en/env-vars), which disables all compaction.

715

716 For example, an ID that contains a Claude model name that Claude Code knows, such as `anthropic/claude-opus-4-8`, `us.anthropic.claude-…-v1:0`, or the dated `claude-sonnet-4-5@20250929`, resolves to that model. This includes IDs that also contain `[1m]`: Claude Code resolves `claude-opus-4-8[1m]` to Opus 4.8 even with `CLAUDE_CODE_DISABLE_1M_CONTEXT` set.

717

695718For a model ID Claude Code doesn't recognize, set [`CLAUDE_CODE_DISABLE_UNKNOWN_MODEL_WINDOW_ENFORCEMENT=1`](/docs/en/env-vars) to have Claude Code compact only after the API rejects the conversation with a [too-long error Claude Code recognizes](/docs/en/errors#prompt-is-too-long). Claude Code doesn't run that recovery when a gateway [rewrites the error](/docs/en/llm-gateway-connect#troubleshoot-gateway-errors) to wording Claude Code doesn't recognize.

696719

697720## Checking your current model

from line 788

765788

766789Apply the same pattern for `ANTHROPIC_DEFAULT_FABLE_MODEL`, `ANTHROPIC_DEFAULT_SONNET_MODEL`, and `ANTHROPIC_DEFAULT_HAIKU_MODEL`. For current and legacy model IDs across all providers, see [Models overview](https://platform.claude.com/docs/en/about-claude/models/overview). To upgrade users to a new model version, update these environment variables and redeploy.

767790

768To enable [extended context](#extended-context) for a pinned model, append `[1m]` to the model ID in `ANTHROPIC_DEFAULT_OPUS_MODEL` or `ANTHROPIC_DEFAULT_SONNET_MODEL`:

791To enable [extended context](#extended-context) for a pinned model, append `[1m]` to the model ID in `ANTHROPIC_DEFAULT_OPUS_MODEL`, `ANTHROPIC_DEFAULT_SONNET_MODEL`, or `ANTHROPIC_DEFAULT_FABLE_MODEL`:

769792

770793```bash theme={null}

771794export ANTHROPIC_DEFAULT_OPUS_MODEL='claude-opus-4-8[1m]'

772795```

773796

774The `[1m]` suffix applies the 1M context window to all usage of the `opus` and `sonnet` aliases, including the plan-mode Opus phase of [`opusplan`](#opusplan-model-setting).

797With the `[1m]` suffix, the 1M context window applies to all usage of the pinned alias, including the plan-mode Opus phase of [`opusplan`](#opusplan-model-setting) and [subagents](/docs/en/sub-agents#choose-a-model) whose `model` frontmatter names the alias.

775798

776799* Claude Code strips the suffix before sending the model ID to your provider.

777800* Only append `[1m]` when the underlying model [supports 1M context](https://platform.claude.com/docs/en/build-with-claude/context-windows#context-window-sizes-by-model).

remote-control Changed · +11 / -4 lines

from line 44

4444 claude remote-control

4545 ```

4646

47 Until you accept Remote Control's one-time confirmation, `claude remote-control` explains what it does and asks `Enable Remote Control? (y/n)` before starting the server. Answer `y` to accept and start the server. If you decline, Claude Code exits without starting the server and asks again the next time you run the command.

4749 The process stays running in your terminal in server mode, waiting for remote connections. It displays a session URL you can use to [connect from another device](#connect-from-another-device), and you can press spacebar to show a QR code for quick access from your phone. While a remote session is active, the terminal shows connection status and tool activity.

4850

4951 Available flags:

from line 102

100102

101103 This starts a Remote Control session that carries over your current conversation history.

102104

105 Until you accept Remote Control's one-time confirmation, a dialog appears before `/remote-control` connects. Select **Enable Remote Control** to accept and connect. If you select **Never mind** or press Esc, Claude Code doesn't connect and asks again the next time you run `/remote-control`.

106

103107 The `--verbose`, `--sandbox`, and `--no-sandbox` flags are not available with this command.

104108 </Tab>

105109

from line 170

166170

167171* **Compaction and `/clear`**: while Claude Code [compacts the conversation](/docs/en/context-window#what-survives-compaction), connected devices show the progress and then where the conversation was compacted. When you run `/clear`, the conversation resets on connected devices too.

168172* **Switching conversations with `/resume`**: the connected device doesn't receive the switched-to conversation's title or earlier history, but new messages in both directions go to and from whichever conversation is open in your terminal. To work on the original conversation from the device again, run `/resume` in your terminal and switch back to it.

173* **Pulling a session with `/teleport`**: when you pull a [Claude Code on the web session](/docs/en/claude-code-on-the-web#from-web-to-terminal) into your terminal with `/teleport`, the connected device doesn't receive the pulled conversation's earlier history. New messages in both directions go to and from the pulled conversation, which is now the one open in your terminal.

169174* **Messages from your other sessions**: with [cross-session messaging](/docs/en/cross-session-messaging), the same connection carries messages between your own sessions on different machines and from your [Claude Code on the web](/docs/en/claude-code-on-the-web) sessions, through Anthropic servers like the rest of Remote Control traffic. [Message sessions on other machines](/docs/en/cross-session-messaging#message-sessions-on-other-machines) covers the delivery rules and [Control inbound messages](/docs/en/cross-session-messaging#control-inbound-messages) covers the inbound controls. Requires Claude Code v2.1.224 or later.

170175* **Prompts you send mid-turn**: when you send a prompt from a connected device before the current turn ends, Claude Code queues it and keeps it in the device's transcript after that turn finishes.

171176* **Diff of your changes**: when the session's directory is in a git repository, a connected device's diff pane shows the diff of your uncommitted changes. The device requests the diff over the connection, and Claude Code computes it on your machine. When your working tree is clean, Claude Code instead serves your branch's changes since it diverged from the default branch. Before v2.1.247, Claude Code reported the diff to connected devices only in sessions served by `claude remote-control`.

172* **Model**: when you pick a [model](/docs/en/model-config) from a connected device, Claude Code runs the session on that model. The terminal's `/model` picker, `/status`, and `/config` show that model. A pick from the device's model control lasts for the current session only. `/model <name>` sent from the device also sets your default for new sessions, the same as typing it in the terminal.

173* **Effort level**: when you set the [effort level](/docs/en/model-config#adjust-effort-level) from a connected device, with `/effort` or the device's effort control, Claude Code applies it to the session on your machine, and claude.ai/code shows the level the session is using. If you pinned a level with `CLAUDE_CODE_EFFORT_LEVEL`, the session keeps that level, and Claude Code refuses a different pick from the effort control. A level you pick from the effort control applies to the current session only and doesn't change your saved default. Picking a level from the effort control requires Claude Code v2.1.234 or later on your machine.

177* **Model**: when you pick a [model](/docs/en/model-config) from a connected device, Claude Code runs the session on that model. The terminal's `/model` picker, `/status`, and `/config` show that model. Requires Claude Code v2.1.238 or later.

178 * A model you pick from the device's model control applies to the current session only. When you send `/model <name>` from the device to an interactive session, Claude Code also sets your default for new sessions.

179 * If you send a name Claude Code doesn't recognize, such as a display name where a model ID is expected, Claude Code [refuses the pick](/docs/en/errors#model-is-not-a-recognized-model-id) and the session keeps its current model. Before v2.1.260, Claude Code saved an unrecognized pick from the device's model control, and your next message failed.

180* **Effort level**: when you set the [effort level](/docs/en/model-config#adjust-effort-level) from a connected device, with `/effort` or the device's effort control, Claude Code applies it to the session on your machine, and claude.ai/code shows the level the session is using. If you pinned a level with `CLAUDE_CODE_EFFORT_LEVEL`, the session keeps that level, and Claude Code refuses a different pick from the effort control. Picking a level from the effort control requires Claude Code v2.1.234 or later on your machine.

174181* **Reconnecting after a connection failure**: run `/remote-control` to reconnect. If compaction rewrote the conversation or you switched conversations with `/resume` in the meantime, Claude Code archives the server session it was using instead of leaving it in the session list. You can still find it by [filtering for archived sessions](/docs/en/claude-code-on-the-web#archive-sessions). Switching conversations while a device is still connected doesn't archive the session.

175182

176183### Enable Remote Control for all sessions

from line 324

317324

318325* **One remote session per interactive process**: outside of server mode, each Claude Code instance supports one remote session at a time. Use [server mode](#start-a-remote-control-session) to run multiple concurrent sessions from a single process.

319326* **Local process must keep running**: Remote Control runs as a local process. If you close the terminal, quit VS Code, or otherwise stop the `claude` process, the session goes offline until you [bring it back](#resume-sessions-after-stopping-the-server). Unless Claude is in the middle of a task, claude.ai and the Claude app show the session as offline within seconds after the process exits. To keep a session running on a remote machine after you disconnect from SSH, start it inside `tmux` or `screen`.

320* **Crashed sessions in server mode**: if a session served by `claude remote-control` crashes, send it a message from a connected device. Claude Code serves it again. You don't have to restart the server.

327* **Crashed sessions in server mode**: if a session served by `claude remote-control` crashes, send it a message from a connected device. Claude Code serves it again. You don't have to restart the server. Requires Claude Code v2.1.238 or later.

321328* **HTTP 403 refusals on a connected session**: once an interactive session is connected, Claude Code keeps retrying for up to three minutes when something between your machine and Anthropic's servers answers with HTTP 403, as can happen after a VPN or network change. If the refusals last longer, Claude Code disconnects, and the reason names what refused: a network edge, or a proxy, VPN, or firewall on your own network.

322329* **Extended network outage**: if your machine is awake but can't reach the network, what you do next depends on the mode:

323330 * **Server mode**: Claude Code gives up after roughly 10 minutes and the `claude remote-control` process exits. Run `claude remote-control` again to start a new session.

from line 332

325332* **Presence heartbeats failing**: if an interactive session disconnects with `could not reach the Remote Control server for about 30 minutes`, run `/remote-control` to reconnect. Claude Code shows this message only when the session's presence heartbeats have been failing while the rest of the connection stayed up; it re-registers the session for about 30 minutes before disconnecting.

326333* **Forwarded dialogs expire**: Claude Code keeps permission prompts and `AskUserQuestion` questions open until you answer them. When Claude Code forwards another kind of dialog to the remote session, such as the model-choice prompt shown after a safety refusal, it waits five minutes by default, then closes the dialog and continues with the dialog's no-action default. The mid-session [Fable usage-credits consent prompt](/docs/en/model-config#fable-and-usage-credits) follows the same deadline but isn't forwarded: Claude Code shows it only in the terminal where the session runs, and if nobody has answered there by the deadline, it ends the turn without sending the request. Your model selection is unchanged, and Claude Code asks again on your next message. Set [`dialogExpiry`](/docs/en/settings-reference#dialogexpiry) to adjust or disable the deadline. Requires Claude Code v2.1.224 or later. Claude Code applies the same deadline to the approval dialog for a held cross-session message. [The held-message expiry rules](/docs/en/cross-session-messaging#control-inbound-messages) cover the cases where Claude Code keeps the dialog open past it.

327334* **Some commands are local-only**: commands that only run in the terminal interface, such as `/plugin` or `/resume`, work only from the local CLI, whether or not you pass an argument. The following work from mobile and web:

328 * Text-output commands: `/compact`, `/clear`, `/context`, `/usage`, `/exit`, `/usage-credits` (prints the billing URL instead of opening a browser), `/recap`, `/reload-plugins`

335 * Text-output commands: `/compact`, `/clear`, `/context`, `/usage`, `/exit`, `/usage-credits`, `/recap`, and `/reload-plugins`. `/usage-credits` prints the billing URL instead of opening a browser. `/reload-plugins` works only when the session runs in an interactive terminal; a session without one declines it.

329336 * `/model`, `/effort`, `/fast`, `/color`, and `/rename`: pass the value as an argument, for example `/model sonnet` or `/effort high`. From mobile and web, `/model` and `/effort` take the argument in place of the terminal picker or slider.

330337 * `/mcp`: from the mobile app, returns a text summary of server status instead of opening the picker. On the web, `/mcp` on its own opens a directory of [claude.ai connectors](/docs/en/mcp#use-mcp-servers-from-claude-ai) instead of returning the summary. The `reconnect`, `enable`, and `disable` [subcommands](/docs/en/commands#all-commands) work from both. Unlike the local CLI, `/mcp reconnect` without a server name reconnects every server that has failed or needs authentication.

331338 * `/config`, from v2.1.181: from the mobile app, pass `key=value` to set a setting, or run it with no argument to list the keys you can set. On the web, `/config` opens the Claude Code section of your settings instead, and ignores text after the command.

sessions Changed · +4 / -2 lines

from line 12

1212

1313| Command | What it does |

1414| :---------------------------------- | :--------------------------------------------------------------------------------------------------------------------- |

15| `claude --continue` | Resumes the most recent interactive session in the current directory |

15| `claude --continue` | Reopens the most recent conversation in the current directory |

1616| `claude --resume` | Opens the [session picker](#use-the-session-picker) |

1717| `claude --resume <name>` | Resumes the named session directly |

1818| `claude --resume <transcript-path>` | Resumes the conversation stored in the `.jsonl` [transcript file](#where-transcripts-are-stored) at that absolute path |

from line 19

1919| `claude --from-pr <number>` | Opens the session picker filtered to sessions linked to that pull request |

2020| `/resume` | Switches to a different conversation from inside an active session |

2121

22Claude Code leaves sessions created with [`claude -p`](/docs/en/headless) or the [Agent SDK](/docs/en/agent-sdk/overview) out of the session picker and out of `claude --continue`. You can still resume one by passing its session ID to `claude --resume <session-id>`. With `claude --continue`, Claude Code also skips [background sessions](/docs/en/agent-view) and [sessions whose first prompt was `/loop`](#where-the-session-picker-looks). When you run [`claude -p --continue`](/docs/en/headless#continue-conversations), Claude Code includes `-p`, SDK, and `/loop` sessions and still skips background sessions.

22Claude Code leaves sessions created with [`claude -p`](/docs/en/headless) or the [Agent SDK](/docs/en/agent-sdk/overview) out of the session picker and out of `claude --continue`. You can still resume one by passing its session ID to `claude --resume <session-id>`. With `claude --continue`, Claude Code also skips [sessions whose first prompt was `/loop`](#where-the-session-picker-looks). When you run [`claude -p --continue`](/docs/en/headless#continue-conversations), Claude Code includes `-p`, SDK, and `/loop` sessions.

24`claude --continue` opens a [background session](/docs/en/agent-view) that has finished, but not one that is still running; opening finished background sessions requires Claude Code v2.1.257 or later. If your most recent conversation is one you [moved to the background](/docs/en/agent-view#send-the-session-to-the-background) and it is still running there, Claude Code exits with `Your most recent conversation is running in the background` and that session's ID. Attach to the session from [`claude agents`](/docs/en/agent-view#attach-to-a-session), or run `claude --resume` to pick another one.

2325

2426You can run `claude --resume <session-id>` from any directory: Claude Code looks for the ID in the current project directory and its git worktrees first, then in every other project on this machine, so it finds a session that started elsewhere or moved with [`/cd`](/docs/en/commands). The cross-project search resolves the ID only when exactly one other project holds a transcript with messages for it, so a hand-copied duplicate makes Claude Code report not-found rather than resume an arbitrary copy. If no stored session matches the ID, Claude Code reports `No conversation found with session ID: <session-id>`. Before v2.1.223, the lookup stopped at the current project directory and its git worktrees, so you had to resume from the directory the session last worked in.

2527

settings-reference Changed · +9 / -3 lines

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from line 878

878878

879879Set a default [effort level](/docs/en/model-config#adjust-effort-level) for models you haven't saved a level for. Lower levels are faster and cheaper on straightforward tasks, and higher levels reason more deeply on complex problems.

880880

881When you run `/effort low`, `medium`, `high`, or `xhigh` in an interactive session on your machine, Claude Code saves the level for the active model under [`modelSettings`](#modelsettings) rather than writing this key. Within the same settings file, Claude Code uses a model's saved level rather than this key; [`modelSettings`](#modelsettings) states the cross-file precedence. In a `-p` run, the Agent SDK, or a session attached to a remote worker, `/effort` applies to that session only. The message that `/effort` prints says which happened. Before v2.1.251, `/effort` wrote this key.

882882

883Within the same settings file, Claude Code uses a model's saved level rather than this key. [`modelSettings`](#modelsettings) states the cross-file precedence.

884

885In a session attached to a remote worker, `/effort` applies to that session only. In a `-p` run or the Agent SDK it also applies to that session only, [unless a hold on the model's default effort is in effect](/docs/en/model-config#non-interactive-effort). [Adjust effort level](/docs/en/model-config#adjust-effort-level) lists the interactive picks that also apply to that session only. The message that `/effort` prints says which happened.

886

883887* **Scope**: [`Any file`](#scopes)

884888* **Type**: string, one of:

885889 * `"low"`: the least reasoning, for short, scoped, latency-sensitive tasks that aren't intelligence-sensitive

from line 899

895899}

896900```

897901

898On Opus 4.7, Opus 4.8, and Fable 5, Claude Code holds that model's default effort, organization-set or built-in, until you change effort once, for example with an interactive `/effort`, the `/model` picker's effort slider, or `--effort` at launch. After that, Claude Code resolves effort by the precedence stated at [`modelSettings`](#modelsettings). See [Adjust effort level](/docs/en/model-config#adjust-effort-level).

902On Opus 4.7, Opus 4.8, and Fable 5, Claude Code holds that model's default effort, organization-set or built-in; [Adjust effort level](/docs/en/model-config#adjust-effort-level) states which ways of setting a level end the hold and which leave it in place. Once the hold ends, Claude Code resolves effort by the precedence stated at [`modelSettings`](#modelsettings).

899903

900904### `enforceAvailableModels`

901905

from line 1130

11261130

11271131### `modelSettings`

11281132

1129Requires Claude Code v2.1.251 or later. Save an [effort level](/docs/en/model-config#adjust-effort-level) for each model you use. In an interactive session on your machine, when you run `/effort low`, `medium`, `high`, or `xhigh` or move the `/model` picker's effort slider, Claude Code saves that level here under the model you're using, so you rarely edit this key yourself. The [`effortLevel`](#effortlevel) entry lists the sessions in which `/effort` applies to that session only. Edit the key by hand to change or remove a level you saved.

1133Save an [effort level](/docs/en/model-config#adjust-effort-level) for each model you use. In an interactive session on your machine, when you save `low`, `medium`, `high`, or `xhigh` as your default with `/effort` or the `/model` picker's effort slider, Claude Code writes that level here under the model you're using, so you rarely edit this key yourself. The [`effortLevel`](#effortlevel) entry lists the sessions where `/effort` applies to that session only. Requires Claude Code v2.1.251 or later.

11301134

1135Edit the key by hand to change or remove a level you saved.

1136

11311137A model's entry here takes precedence over [`effortLevel`](#effortlevel) in the same settings file. Across files, Claude Code resolves each model separately: the highest-precedence [settings file](/docs/en/settings#settings-precedence) that sets either that model's entry or `effortLevel` decides, so an `effortLevel` in managed settings outranks a level you saved in user settings. [Adjust effort level](/docs/en/model-config#adjust-effort-level) lists what else can override a saved level, such as `--effort` at launch.

11321138

11331139* **Scope**: [`Any file`](#scopes)

from line 3283

32773283* `cooldownSessions`: after Claude Code shows the `gateway-errors` tip, it doesn't show that tip again until five sessions later.

32783284* `priority`: when the `gateway-errors` tip and another tip have gone unshown for the same number of sessions, for example when neither has been shown yet, Claude Code shows `gateway-errors` first. The plain string has the default priority, `0`.

32793285

3280While Claude works, Claude Code shows your tips in the spinner with your prefix, such as `Acme tip: Run /review before opening a PR`.

3281

3282### `spinnerVerbs`

3283

3284While a turn is in progress, the spinner shows a rotating verb such as "Accomplishing", "Architecting", or "Baking". Use this key to add your own verbs to that rotati

3286While Claude works, Claude Code shows your tips in the spinner with your prefi

sub-agents Changed · +5 / -3 lines

from line 887

887887* When a subagent finishes successfully, Claude Code removes its row immediately and, except in [screen reader mode](/docs/en/accessibility), shows `/tasks to see subagents` in the footer for 30 seconds. During those 30 seconds, run [`/tasks`](/docs/en/commands) and press `Enter` on the subagent to open its transcript. Before v2.1.232, Claude Code kept the row for 30 seconds after the subagent finished, the same as a failed one, and showed no footer hint.

888888* When a subagent fails or you stop it, Claude Code keeps its row for 30 seconds. To clear the row sooner, select it and press `x`.

889889

890A background subagent that completes stays listed in [`/tasks`](/docs/en/commands), marked done and sorted below running work, for the same window as the footer hint above. Its detail view stays open when the subagent finishes. Subagents that fail or that you stop leave the list. Before v2.1.208, a completed subagent left the list the moment it finished and its detail view closed.

890A background subagent that completes stays listed in [`/tasks`](/docs/en/commands), marked done and sorted below running work, for the same 30 seconds as the footer hint. Its detail view stays open when the subagent finishes. Subagents that fail or that you stop leave the list. Before v2.1.208, a completed subagent left the list the moment it finished and its detail view closed.

891891

892892### Subagent names

893893

from line 1045

10451045

10461046Each subagent invocation creates a new instance rather than continuing an earlier one. To continue an existing subagent's work instead of starting over, ask Claude to resume it.

10471047

1048Resumed subagents retain their full conversation history, including all previous tool calls, results, and reasoning. The subagent picks up exactly where it stopped rather than starting fresh.

1048Resumed subagents retain their full conversation history, including all previous tool calls, results, and reasoning. If the subagent spawned [background subagents of its own](#let-subagents-spawn-their-own-subagents), that history includes the results they delivered while it ran. The subagent picks up exactly where it stopped rather than starting fresh.

10491049

10501050* When a subagent completes, Claude receives its agent ID.

10511051* The built-in Explore and Plan agents are one-shot and return no agent ID, so Claude can't resume them. Use `general-purpose` or a custom subagent when you need to continue the work.

from line 1063

10631063[Claude resumes the subagent with full context from previous conversation]

10641064```

10651065

1066A completed subagent that receives a `SendMessage` auto-resumes in the background without a new `Agent` invocation. The same applies to a subagent that Claude stopped with the `TaskStop` tool.

1066When Claude sends a completed subagent a message with the `SendMessage` tool, the subagent resumes in the background without a new `Agent` invocation. The same applies to a subagent that Claude stopped with the `TaskStop` tool, once its stopped run has exited.

1067

1068A subagent that has the `SendMessage` tool can send that message too. In an interactive session, the resumed agent then reports back to the subagent that resumed it, not to your main conversation. That subagent waits for the result before finishing its own work. When a subagent messages an agent it reports to, such as its own launcher, Claude Code resumes that agent without redirecting its results.

10671069

10681070A subagent you stopped yourself, with `x` in `/tasks` or an SDK `stop_task` request, doesn't auto-resume. If Claude sends it a message, the message is refused and Claude is told the agent was cancelled.

10691071

worktrees Changed · +12 / -4 lines

from line 321

321321

322322In most cases the rest of the message says the directory's git metadata resolves into the main checkout: for example, its `.git` file points at the main repository's own `.git` directory, or git resolves its working tree to the main checkout through a `core.worktree` redirect. From such a directory, an ordinary git command such as `git reset --hard` would act on the main checkout instead of the worktree. Claude Code also refuses when the directory has a `.git` entry it can't read, rather than assuming the worktree is safe.

323323

324A directory with no git metadata at all, such as one your [`WorktreeCreate` hook](#non-git-version-control) creates, passes the check only when no git repository contains it. If the hook creates the directory inside a repository, git resolves it to that repository's checkout and Claude Code refuses it with the `git resolves its working tree to` message, so have the hook create its directories outside any repository.

325

324326Claude Code leaves the refused directory in place, since it may hold work. Match the message to its recovery, whether it follows `Refusing to use <path>` or appears in a [resume message](#the-session-resumes-outside-its-worktree); some endings occur only in resume messages:

325327

326328* **Says `launch from the parent checkout` or `Run the resume from the project checkout`**: you launched Claude Code from inside the worktree. Launch from the main checkout instead; the worktree needs no recreation.

from line 334

332334

333335### The session resumes outside its worktree

334336

335When an interactive resume can't return the session to its worktree, Claude Code says so with one of the messages below.

337When you resume a session interactively and Claude Code can't return it to its worktree, Claude Code says so with one of the messages below. When Claude Code clears the worktree binding, it records the clear in the session transcript. If you [suppress transcript writes](/docs/en/sessions#where-transcripts-are-stored), the message says instead that the binding could not be cleared and that Claude Code will re-check the worktree on a later resume.

336338

337339| Message starts with | What happened and what to do |

338340| :------------------------------------------------ | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

from line 343

341343| `Did not re-enter your worktree <path>` | Claude Code refused the worktree binding as unsafe; it clears the binding and the session continues without isolation. The message includes the specific refusal: match it under [Claude Code refuses to use a worktree](#claude-code-refuses-to-use-a-worktree), since the fix is recreation for some refusals and a path change for others. |

342344| `Could not re-enter your worktree <path>` | Claude Code couldn't vouch for the worktree from where you launched, most commonly because you launched from inside it; the binding is kept. The rest of the message names the fix; match it under [Claude Code refuses to use a worktree](#claude-code-refuses-to-use-a-worktree). |

343345

344In [non-interactive mode](/docs/en/headless) with `-p`, and on resumes the [Agent SDK](/docs/en/agent-sdk/sessions) runs, Claude Code stops the resume with a stderr error for every refusal except a gone worktree, instead of continuing without isolation, and the messages take different shapes from the ones in the table above:

346In [non-interactive mode](/docs/en/headless) with `-p`, and on resumes that the [Agent SDK](/docs/en/agent-sdk/sessions) runs, Claude Code stops the resume with a stderr error for every refusal except a gone worktree, instead of continuing without isolation.

345347

346* `Error: cannot resume into worktree <path>: ...This session was not started.` for a refusal the table shows as `Did not re-enter`

348With `--output-format stream-json`, the refusal also arrives on stdout as a `result` message with subtype `error_during_execution` whose `errors` array carries the same text, so an Agent SDK application receives the reason rather than only a non-zero exit. Before v2.1.260, a worktree-resume refusal produced no `result` message.

349

350The messages take different shapes from the interactive messages in the table:

351

352* `Error: cannot resume into worktree <path>: ...This session was not started.` for a refusal the table shows as `Did not re-enter`. Claude Code clears the worktree binding before exiting, and the error says so; the next time you resume the conversation, the session continues in the current directory without worktree isolation. Before v2.1.260, Claude Code didn't write the cleared binding, so every retry of the same resume failed with the same error.

353

354 If you [suppress transcript writes](/docs/en/sessions#where-transcripts-are-stored), the clear can't be saved. The error then says the same command will be refused again, and names `--fork-session` and starting a new conversation as ways to continue without the worktree.

347355* `Error: could not verify worktree <path> for this resume, so the resume was aborted...` for `Could not verify`

348356* `Error: ...The worktree binding is kept.` for `Could not re-enter`

349357* `Notice: the worktree <path> for this session no longer exists...` for a gone worktree; Claude Code prints it and continues the session, as an interactive resume does

advisor Changed · +1 / -1 lines

from line 84

8484| Opus 4.7 or later | Fable, and Opus 4.7 or later | Opus 4.7 and later Opus models are ranked as equally capable, so any of them accepts another as an advisor. An Opus 4.7 main with an Opus 4.6 or Sonnet 5 advisor is rejected |

8585| Fable 5.1 or Fable 5 | Fable 5.1, or the same Fable version | An Opus or Sonnet advisor is rejected, and so is a Fable 5 advisor for a Fable 5.1 main model |

8686

87Fable 5.1 requires Claude Code v2.1.255 or later and Fable 5 requires v2.1.170 or later, plus [Fable access](/docs/en/model-config#work-with-fable).

87Fable 5.1 requires Claude Code v2.1.257 or later, and Fable 5 requires v2.1.170 or later. Both require [Fable access](/docs/en/model-config#work-with-fable).

8888

8989Set the advisor as `fable`, `opus`, or `sonnet`. These aliases resolve to Claude Code's built-in default version for each model family, which advances with new Claude Code releases. You can also pass a full model ID such as `claude-opus-5`.

9090

artifacts Changed · +1 / -1 lines

from line 52

5252* You have since [shared it publicly](#share-an-artifact)

5353* You have since shared it with specific people or your organization with the latest version chosen as the version viewers see

5454

55After the first publish, Claude prints the URL, and your browser opens to the new page. Press `Ctrl+]` at any time to reopen the most recent artifact from the terminal.

55After the first publish, Claude prints the URL, and your browser opens to the new page. If you sent the prompt through [Remote Control](/docs/en/remote-control) from claude.ai, Claude Desktop, or the Claude mobile app, no tab opens on the machine running the session. The browser opens there the next time Claude publishes the artifact from a prompt you type at the terminal. Press `Ctrl+]` at any time to reopen the session's most recent artifact.

5656

5757Claude picks the artifact's title and an emoji for its browser-tab icon. Both appear in your [gallery of artifacts](#share-an-artifact) on claude.ai and in shared links, so ask Claude to use a specific title or icon if you want one.

5858

claude-security Changed · +1 / -1 lines

from line 134

134134

135135**The `/claude-security` menu opens with a Python warning.** The plugin needs `python3` 3.9 or later on your `PATH`. When it can't find `python3` at all, the menu warns that Claude Security won't work until one is installed; when the first `python3` on your `PATH` is older, the warning names the version it found. Install Python 3, or put a newer `python3` first on your `PATH`, then start a new session.

136136

137**You may see "Fable 5.1's safeguards flagged this message" or "Fable 5's safeguards flagged this message" when using a Fable model.** Due to Fable's cybersecurity safety classifiers, certain model activities will be blocked and automatically downgraded to Opus. This is expected, and the scan should still complete successfully.

137**You may see a "safeguards flagged this message" notice when scanning on a Fable model.** The message names the model, for example "Fable 5.1's safeguards flagged this message". Fable's cybersecurity safety classifiers flag certain requests, and Claude Code re-runs a flagged request on an Opus model through [automatic model fallback](/docs/en/model-config#automatic-model-fallback). This is expected, and the scan should still complete successfully.

138138

139139## Related resources

140140

cli-reference Changed · +1 / -1 lines

from line 71

7171| `--channels` | (Research preview) MCP servers whose [channel](/docs/en/channels) notifications Claude should listen for in this session. Space-separated list of `plugin:<name>@<marketplace>` entries. Requires Anthropic authentication through claude.ai or a Console API key | `claude --channels plugin:my-notifier@my-marketplace` |

7272| `--chrome` | Enable [Chrome browser integration](/docs/en/chrome) for web automation and testing | `claude --chrome` |

7373| `--cloud` | With a task description, create a new [web session](/docs/en/claude-code-on-the-web) on claude.ai. With a session ID (`session_...` or `cse_...`) or a claude.ai/code URL, queue a message into that existing session instead, with `-p`. See [send a follow-up message](/docs/en/claude-code-on-the-web#send-follow-ups-from-the-cli). | `claude --cloud "Fix the login bug"` |

74| `--continue`, `-c` | Load the most recent conversation in the current directory, skipping [background sessions, sessions created with `claude -p` or the Agent SDK, and sessions whose first prompt was `/loop`](/docs/en/sessions#resume-a-session). `claude -p --continue` includes `-p`, SDK, and `/loop` sessions. Includes sessions that added this directory with `/add-dir` | `claude --continue` |

74| `--continue`, `-c` | Load the most recent conversation in the current directory, including a [background session that has finished](/docs/en/sessions#resume-a-session); opening finished background sessions requires Claude Code v2.1.257 or later. Skips sessions created with `claude -p` or the Agent SDK, and sessions whose first prompt was `/loop`. `claude -p --continue` includes `-p`, SDK, and `/loop` sessions. Includes sessions that added this directory with `/add-dir` | `claude --continue` |

7575| `--dangerously-load-development-channels` | Enable [channels](/docs/en/channels-reference#test-during-the-research-preview) that are not on the approved allowlist, for local development. Accepts `plugin:<name>@<marketplace>` and `server:<name>` entries. Prompts for confirmation | `claude --dangerously-load-development-channels server:webhook` |

7676| `--dangerously-skip-permissions` | Skip permission prompts. Equivalent to `--permission-mode bypassPermissions`. See [permission modes](/docs/en/permission-modes#skip-all-checks-with-bypasspermissions-mode) for what this does and does not skip. For sessions started with `--bg`, the mode [persists when the supervisor restarts the session](/docs/en/agent-view#permission-mode-model-and-effort) | `claude --dangerously-skip-permissions` |

7777| `--debug` | Enable debug mode with optional category filtering, such as `--debug='mcp,startup'` or `--debug='!1p'`. The filter binds only in the `=` form; a space-separated filter enables debug mode without filtering | `claude --debug='mcp,startup'` |

context-window Changed · +3 / -1 lines

from line 1620

16201620* **Clear between tasks**: run `/clear` when switching to unrelated work. Old conversation crowds out the files you need next and costs tokens on every message.

16211621* **Delegate large reads**: send research to a [subagent](/docs/en/sub-agents) so the file contents stay in its context window, not yours.

16221622

1623If you need a larger window rather than a smaller conversation, Fable 5.1, Fable 5, Sonnet 5, Opus 4.6 and later, and Sonnet 4.6 support a 1 million token context window. See [Extended context](/docs/en/model-config#extended-context) for availability by plan and how to select a `[1m]` model variant. Sonnet 5 runs at 1M with no `[1m]` variant to select; see [Sonnet 5 context window](/docs/en/model-config#sonnet-5-context-window) for its auto-compaction thresholds and the LLM gateway exception. Compaction works the same way at the larger limit.

1623If you need a larger window rather than a smaller conversation, Fable models, Sonnet 5, Opus 4.6 and later, and Sonnet 4.6 support a 1 million token context window. See [Extended context](/docs/en/model-config#extended-context) for availability by plan and how to select a `[1m]` model variant. Compaction works the same way at the larger limit.

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1625Sonnet 5 runs with the 1M context window and has no `[1m]` variant to select. See [Sonnet 5 context window](/docs/en/model-config#sonnet-5-context-window) for its auto-compaction thresholds and the LLM gateway exception.

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16251627The point where automatic compaction runs depends on your model and configuration. See [Default auto-compact thresholds](/docs/en/model-config#default-auto-compact-thresholds) for the boundaries per model, and [Correct the window for a gateway or custom model ID](/docs/en/model-config#correct-the-window-for-a-gateway-or-custom-model-id) if Claude Code assumes the wrong window for your model ID, such as an [LLM gateway](/docs/en/llm-gateway) alias.

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129129### Effort level

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131A setting that controls how much of the adaptive-reasoning thinking budget Claude uses on each turn. Higher effort means more thinking tokens and deeper reasoning; lower effort is faster and cheaper. Effort is supported on Fable 5.1 and Fable 5, on Opus 4.6 and later, and on Sonnet 4.6 and later.

131A setting that controls adaptive reasoning, which lets the model decide whether and how much to think on each step. Higher effort means more thinking tokens and deeper reasoning; lower effort is faster and cheaper. Effort is supported on Fable models, on Opus 4.6 and later, and on Sonnet 4.6 and later.

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133133Learn more: [Adjust effort level](/docs/en/model-config#adjust-effort-level)

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319319

320320### Continue conversations

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322Use `--continue` to continue the most recent conversation, or `--resume` with a session ID to continue a specific conversation. `--continue` skips [background sessions](/docs/en/sessions#resume-a-session). This example runs a review, then sends follow-up prompts:

322Use `--continue` to continue the most recent conversation, or `--resume` with a session ID to continue a specific conversation. On Claude Code v2.1.257 or later, when you pass `--continue`, Claude Code opens a [background session](/docs/en/sessions#resume-a-session) that has finished, but not one that is still running. This example runs a review, then sends follow-up prompts:

323323

324324```bash theme={null}

325325# First request

One read of Claude Code CLI

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