Model configuration changedmodel-config
Nearest release: v2.1.267, published an hour after this site recorded the change. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.
Recorded here
Lines+51added
Lines−28removed
From line
26
where the diff opens
First seen
14 Aug 2026
this site's first read of the page
Recorded edits74to this page, all time
The whole hunk
from line 26, old and new numbered
/
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.
50
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`.
52
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-`
from line 408
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).
No line in this hunk matches that.