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Model configuration
model-config
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model-config Changed · +43 / -17 lines
#### Set a default model for new sessions
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| Model alias | Behavior | | ---------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -| **`default`** | Special value that clears any model override and reverts to the recommended model for your account type, or to the [organization default model](#organization-default-model) when an admin has set one. Not itself a model alias | +| **`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 | | **`best`** | Uses Fable 5 where your organization has access to it, otherwise the latest Opus model | | **`fable`** | Uses Claude Fable 5 for your hardest and longest-running tasks | | **`sonnet`** | Uses the latest Sonnet model for daily coding tasks |
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2. **At startup**: launch with `claude --model <alias|name>` 3. **Environment variable**: set `ANTHROPIC_MODEL=<alias|name>` 4. **Settings**: configure permanently in your settings file using the `model` field +5. **[Default for new sessions](#set-a-default-model-for-new-sessions)**: set `ANTHROPIC_DEFAULT_MODEL=<alias|name>` As of v2.1.153, `/model` saves your choice as the default for new sessions by writing the `model` field in your user settings. In the picker:
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Resumed sessions started with `claude --resume`, `--continue`, or the `/resume` picker keep the model they were using when the transcript was saved, regardless of the current `model` setting. If the restored model has been retired or is excluded by [`availableModels`](#restrict-model-selection), the session falls through to the normal precedence order. This prevents another session's `/model` choice from changing the model on resume. On providers that use provider-specific deployment IDs rather than Anthropic model IDs, such as Amazon Bedrock, Google Cloud's Agent Platform, and Microsoft Foundry, the transcript model isn't restored at all and the session resolves its model through the normal precedence order. -A model you pick for the new launch with `--model` or `ANTHROPIC_MODEL` still takes precedence over the restored model. As of v2.1.195, so does an [`ANTHROPIC_DEFAULT_OPUS_MODEL`](#environment-variables) family variable. +A model you pick for the new launch with `--model` or `ANTHROPIC_MODEL` still takes precedence over the restored model. As of v2.1.195, so does an [`ANTHROPIC_DEFAULT_OPUS_MODEL`](#environment-variables) family variable. [`ANTHROPIC_DEFAULT_MODEL`](#set-a-default-model-for-new-sessions) can too, under the conditions listed in its section. When 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; the key-level enumeration is under [Settings precedence](/docs/en/settings#settings-precedence).
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} ``` +#### Set a default model for new sessions + +Set `ANTHROPIC_DEFAULT_MODEL=<alias|name>` to choose the model your sessions start on by default. Requires Claude Code v2.1.236 or later. + +Claude Code starts a new session on the variable's model only when none of these selects a model: + +* The `--model` flag +* `ANTHROPIC_MODEL` +* A `model` value in any settings file, including the choice you save with `/model` +* An [organization default model](#organization-default-model) + +A choice you save with `/model` takes precedence over the variable on later launches too. With `ANTHROPIC_MODEL` set instead, Claude Code returns to that variable's model on the next launch, whatever you saved with `/model`. + +Claude Code also resolves the Default option to the variable's model, unless an organization default model applies. When the Default option resolves to the variable's model, the Default row in the `/model` picker shows the label Set by ANTHROPIC\_DEFAULT\_MODEL. + +Claude Code ignores the variable in these cases, and the Default option resolves as if you hadn't set it: + +* You set it to `default`, `inherit`, `opusplan`, or `haiku` +* [`enforceAvailableModels`](#enforce-the-allowlist-for-the-default-model) is on +* [`availableModels`](#restrict-model-selection) or [organization model restrictions](#organization-model-restrictions) exclude the model +* The model isn't available to your account + +When a new session would start on the variable's model, a session you resume with `claude --resume`, `--continue`, or the `/resume` picker starts on it too. Claude Code doesn't restore the model saved in that session's transcript. Otherwise Claude Code doesn't use the variable when you [resume a session](#setting-your-model). + ## Restrict model selection Enterprise administrators can use `availableModels` in [managed or policy settings](/docs/en/settings#settings-files) to restrict which models users can select. Entries match a model family such as `sonnet`, a version prefix such as `claude-sonnet-4-5`, or a full model ID such as `claude-sonnet-4-5-20250929`.
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When `availableModels` is set, the allowlist applies everywhere a user can specify a model: -* **Main session model**: `/model`, the `--model` flag, the `ANTHROPIC_MODEL` environment variable, the `model` setting, and the model restored when [resuming a session](#setting-your-model) +* **Main session model**: `/model`, the `--model` flag, the `ANTHROPIC_MODEL` environment variable, the `model` setting, [`ANTHROPIC_DEFAULT_MODEL`](#set-a-default-model-for-new-sessions), and the model restored when [resuming a session](#setting-your-model) * **Alias resolution**: the `ANTHROPIC_DEFAULT_OPUS_MODEL`, `ANTHROPIC_DEFAULT_SONNET_MODEL`, `ANTHROPIC_DEFAULT_HAIKU_MODEL`, and `ANTHROPIC_DEFAULT_FABLE_MODEL` environment variables cannot redirect an allowed alias to a model outside the list * **Fast mode**: `/fast` refuses to toggle when it would implicitly switch to an Opus model outside the list, with the message "is not in your organization's allowed models" * **Subagent and teammate models**: the `model` field in [subagent](/docs/en/sub-agents#choose-a-model) frontmatter, the Agent tool's `model` parameter, [agent team](/docs/en/agent-teams#specify-teammates-and-models) teammate models, `CLAUDE_CODE_SUBAGENT_MODEL`, and, on v2.1.197 and earlier, the model picker in the `/agents` wizard 
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* **`/model`**: Claude Code rejects the switch with an error * **`--model` flag, `ANTHROPIC_MODEL`, or the `model` setting**: Claude Code replaces the value at startup with a warning naming both the requested and substituted models, and the session starts on the default model +* **[`ANTHROPIC_DEFAULT_MODEL`](#set-a-default-model-for-new-sessions)**: Claude Code ignores the variable * **Subagent or teammate override**: Claude Code falls back to the [subagent's inherited model](/docs/en/sub-agents#choose-a-model) or the [lead's model for a teammate](/docs/en/agent-teams#specify-teammates-and-models) rather than failing the request. In interactive sessions, Claude Code warns you when it substitutes a subagent's model, by this fallback or by the newest-permitted-version substitution above, naming the requested and substituted models; it doesn't report a teammate's fallback. Where the newest-permitted-version substitution above operates, a blocked family alias follows it instead; before v2.1.222, an alias fell back like any other blocked value on every provider * **Skill or command override**: Claude Code ignores the override, including a blocked family alias, and the skill or command runs on the session model. A skill or command that [runs in a subagent](/docs/en/skills#run-skills-in-a-subagent) follows the subagent behavior above instead * **`advisorModel` setting**: the advisor is disabled for the session
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### Default model behavior -The Default option in the model picker is not affected by `availableModels` unless [`enforceAvailableModels`](#enforce-the-allowlist-for-the-default-model) is also set. On its own, `availableModels` leaves Default available, resolving to the system's [runtime default](#default-model-setting) for the account. If that default is a model you intend to restrict, set `enforceAvailableModels` as well. +On its own, `availableModels` leaves the Default option on the system's [runtime default](#default-model-setting) for the account until you also set [`enforceAvailableModels`](#enforce-the-allowlist-for-the-default-model). If that default is a model you intend to restrict, set `enforceAvailableModels` as well. An empty `availableModels` array never engages the Default-model enforcement: with `availableModels: []`, named model selections are blocked but the Default model for the account type remains usable regardless of `enforceAvailableModels`.
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The Default option resolves to the account-type default, or to the [organization default model](#organization-default-model) when an admin has set one. When that model is not in the allowlist, the Default option instead resolves to the first `availableModels` entry that names an allowed, available model, and the `/model` picker's Default row shows that model. This applies everywhere the default is reached: session startup, selecting Default in `/model`, the `"default"` keyword in [fallback model chains](#fallback-model-chains), and the fallback used when an excluded selection is dropped. -`enforceAvailableModels` has no effect when `availableModels` is unset or empty: with `availableModels: []`, the Default model for the account type remains usable, so the setting cannot lock users out of every model. When `availableModels` is non-empty but no entry resolves to an allowed and available model, enforcement is skipped and Default resolves to the account-type default, with a warning visible only under `--debug`. Keep at least one guaranteed-available entry in the list to avoid this. +`enforceAvailableModels` remaps the Default option only when `availableModels` is non-empty. With `availableModels: []`, the Default model for the account type remains usable, so the setting cannot lock users out of every model. When `availableModels` is non-empty but no entry resolves to an allowed and available model, enforcement is skipped and Default resolves to the account-type default, with a warning visible only under `--debug`. Keep at least one guaranteed-available entry in the list to avoid this. Deploy both keys in the [highest-precedence managed source](/docs/en/settings#precedence-within-the-managed-tier): these keys don't merge across managed sources, so a pair placed in a managed settings file is ignored when the admin console delivers any settings.
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* **`availableModels`**: restricts which named models users can switch to * **`enforceAvailableModels`**: extends the `availableModels` allowlist to the Default option, so Default cannot resolve to a model outside the list * **`model`**: sets the initial model selection when a session starts -* **`ANTHROPIC_DEFAULT_SONNET_MODEL`** / **`ANTHROPIC_DEFAULT_OPUS_MODEL`** / **`ANTHROPIC_DEFAULT_HAIKU_MODEL`** / **`ANTHROPIC_DEFAULT_FABLE_MODEL`**: control what the Default option and the `sonnet`, `opus`, `haiku`, and `fable` aliases resolve to +* **`ANTHROPIC_DEFAULT_SONNET_MODEL`** / **`ANTHROPIC_DEFAULT_OPUS_MODEL`** / **`ANTHROPIC_DEFAULT_HAIKU_MODEL`** / **`ANTHROPIC_DEFAULT_FABLE_MODEL`**: control what the `sonnet`, `opus`, `haiku`, and `fable` aliases resolve to, and which version the [account-type default](#default-model-setting) uses This example starts users on Sonnet 4.5, limits the picker to Sonnet and Haiku, and ensures Default resolves to a model on the allowlist rather than the tier default:
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} ``` -Without `enforceAvailableModels` or the `env` block, a user who selects Default in the picker would get the latest release for their tier, bypassing the version pin in `model` and `availableModels`. The two settings cover different scopes: `enforceAvailableModels` makes Default obey the allowlist, while the `env` block pins which version a permitted alias such as `sonnet` resolves to. Use `enforceAvailableModels` alone when restricting model families is enough; add the `env` block when you also need to pin a specific version. +Without `enforceAvailableModels` or the `env` block, a user who selects Default in the picker gets the [runtime default](#default-model-setting) rather than the version pinned in `model`. The two settings cover different scopes: `enforceAvailableModels` makes Default obey the allowlist, while the `env` block pins which version a permitted alias such as `sonnet` resolves to. Use `enforceAvailableModels` alone when restricting model families is enough; add the `env` block when you also need to pin a specific version. ### Merge behavior
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## Organization default model -Organization admins on Claude Enterprise plans can set a default model for Claude Code members from the claude.ai admin console, for the whole organization or per custom role. When one is set, the Default option resolves to that model instead of the [account-type default](#default-model-setting). Requires Claude Code v2.1.196 or later. +Organization admins on Claude Enterprise plans can set a default model for Claude Code members from the claude.ai admin console, for the whole organization or per custom role. When one is set, the Default option resolves to that model. Requires Claude Code v2.1.196 or later. The Default row in the `/model` picker shows the organization default's name with the label Org default. The label reads Org default whether the admin set the default for the whole organization or for your role. A role default covers members of that custom role and takes precedence over the organization-wide default; when several of your roles set different defaults, the most capable model applies. -The organization default is a starting point, not a restriction, and any other model selection takes precedence over it: +The organization default is a starting point, not a restriction. These selections take precedence over it: * the `--model` flag and the `ANTHROPIC_MODEL` environment variable * a `model` value in [managed settings](/docs/en/settings#settings-files) or supplied through `--settings`
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When the organization default doesn't override user selection, the first interactive launch after the admin changes it clears the `model` key from your user settings once, so the new default applies. It changes nothing else in the file, and a model you save with `/model` after that launch is kept. -The organization default passes through the same restriction checks as any other Default model before it is adopted: +The organization default passes through these restriction checks before it is adopted: -* [`availableModels`](#restrict-model-selection) on its own never constrains the Default option, so an organization default outside the allowlist still applies. When [`enforceAvailableModels`](#enforce-the-allowlist-for-the-default-model) is also set, an organization default outside the allowlist is remapped to the first allowlist entry, like any other Default +* [`availableModels`](#restrict-model-selection) on its own doesn't apply to the organization default, so an organization default outside the allowlist still applies. When [`enforceAvailableModels`](#enforce-the-allowlist-for-the-default-model) is also set, an organization default outside the allowlist is remapped to the first allowlist entry, like any other Default * an organization default that [organization model restrictions](#organization-model-restrictions) deny for your account is replaced by the newest allowed model in its family, or a lower-cost family when every version of it is restricted -* an organization default that isn't available to your account at all, such as Fable 5 under [zero data retention](/docs/en/zero-data-retention), is skipped, and the Default option resolves to the account-type default +* an organization default that isn't available to your account at all, such as Fable 5 under [zero data retention](/docs/en/zero-data-retention), is skipped, and the Default option resolves as it would [without an organization default](#default-model-setting) As of v2.1.199, when the organization default is a different model family from your account type's usual default, the `/model` picker keeps a separate row for that usual family, so you can still switch to it for a session. In v2.1.196 through v2.1.198 that row is missing from the picker.
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Before v2.1.219, `default` resolved to Opus 4.8 on the Anthropic API, Max, Team Premium, and Enterprise pay-as-you-go 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, `default` resolved to Opus 4.7 on Claude Platform on AWS and to Sonnet 4.5 on Amazon Bedrock and Google Cloud's Agent Platform. -When an admin has set an [organization default model](#organization-default-model), `default` resolves to that model instead of the account-type default above. Requires Claude Code v2.1.196 or later. +When an admin has set an [organization default model](#organization-default-model), `default` resolves to that model instead of the account-type default above. Requires Claude Code v2.1.196 or later. `default` can also resolve to the model you set with [`ANTHROPIC_DEFAULT_MODEL`](#set-a-default-model-for-new-sessions), under the conditions listed in its section. When 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. -Fable 5 is not the default model on any account type. Sessions use Fable 5 only after you choose it, with `/model fable`, a `model` setting, or the `best` alias where Fable 5 is available. Choosing it with `/model` saves it as the selected model in your user settings, so later sessions start on Fable 5 until you change models. +Fable 5 is not the default model on any account type. Sessions use Fable 5 only after you choose it, for example with `/model fable`, a `model` setting, or the `best` alias where Fable 5 is available. Choosing it with `/model` saves it as the selected model in your user settings, so later sessions start on Fable 5 until you change models. ### `opusplan` model setting
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## Environment variables -Use the following environment variables to control the model names that the aliases map to. Each value must be a full model name, or the equivalent identifier for your API provider. +Use the following environment variables to control the model names that the aliases map to. Each value must be a full model name, or the equivalent identifier for your API provider. To choose the model your sessions start on, set [`ANTHROPIC_DEFAULT_MODEL`](#set-a-default-model-for-new-sessions), which this table omits. | Environment variable | Description | | -------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
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Without pinning, Claude Code uses model aliases such as `fable`, `opus`, `sonnet`, and `haiku` that resolve to a built-in default model ID for each provider. That default can lag the newest Anthropic release, and the model it points to may not yet be enabled in a user's account. When the default is unavailable, Amazon Bedrock and Google Cloud's Agent Platform users see a notice and the session falls back to an earlier version of the default model, or to the default Sonnet model when the default is an Opus model and no Opus version is available. Microsoft Foundry users see errors instead, because Microsoft Foundry has no equivalent startup check. -On Amazon Bedrock and Google Cloud's Agent Platform, a user who starts the session on a specific Sonnet or Opus version, with `--model`, `ANTHROPIC_MODEL`, or the `model` setting, pins that version as the session's default for the matching alias: the startup check skips the built-in default it replaces and shows no fallback notice. Before v2.1.211, the check ran and could show a notice even when a session model was explicitly configured. +On Amazon Bedrock and Google Cloud's Agent Platform, a user who starts the session on a specific Sonnet or Opus version, for example with `--model`, `ANTHROPIC_MODEL`, or the `model` setting, pins that version as the session's default for the matching alias: the startup check skips the built-in default it replaces and shows no fallback notice. Before v2.1.211, the check ran and could show a notice even when a session model was explicitly configured. <Warning> Set the model environment variables to specific version IDs as part of your initial setup. Pinning lets you control when your users move to a new model.
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`low`, `medium`, `high`, and `xhigh` persist across sessions when you set them in an interactive session. `max` provides the deepest reasoning. Unless you set it through the `CLAUDE_CODE_EFFORT_LEVEL` environment variable, `max` applies to the current session only. +<Note> + A level you pick from the effort control on a phone or browser connected through [Remote Control](/docs/en/remote-control#what-connected-devices-see) applies to that session only. +</Note> + A 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 can't release the model-default hold: while the hold is in force, a non-interactive `/effort` reports `Not applied`, so pass `--effort` at launch instead. The `/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. It applies to the current session only.
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* **`--effort` flag**: pass a level name to set it for a single session when launching Claude Code * **Environment variable**: set `CLAUDE_CODE_EFFORT_LEVEL` to a level name or `auto` * **Settings**: set `effortLevel` to `low`, `medium`, `high`, or `xhigh` in your settings file. `max` and `ultracode` are [session-only](#adjust-effort-level) and are not accepted here +* **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 * **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 The environment variable takes precedence over all other methods, then your configured level, then the model default. Frontmatter effort applies when that skill or subagent is active, overriding the session level but not the environment variable.
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* 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. * 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. -For 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 Anthropic's too-long error; that recovery doesn't run when a gateway [rewrites the error](/docs/en/llm-gateway-connect#troubleshoot-gateway-errors). +For 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. ## Checking your current model
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To turn off 1M context, set `CLAUDE_CODE_DISABLE_1M_CONTEXT=1`. Claude Code removes 1M model variants from the model picker. On models with a native 1M window, such as Sonnet 5 and Fable 5, it also treats the model as having a 200K context window: * With auto-compaction on, sessions compact at the 200K boundary through [auto-compaction](#set-the-auto-compact-window). Setting the auto-compact window above 200K doesn't lift the hold, because Claude Code caps that window at the model's context window. -* With auto-compaction off, sessions stop at the 200K boundary with a [`Prompt is too long` error](/docs/en/errors#prompt-is-too-long) instead of compacting. +* With auto-compaction off, sessions stop at the 200K boundary with the [context-limit error](/docs/en/errors#prompt-is-too-long) instead of compacting. Before v2.1.223, Claude Code held only Sonnet 5, Opus 4.8, and Opus 5 sessions to 200K. See [environment variables](/docs/en/env-vars).
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* **Subagent or teammate override**: Claude Code falls back to the [subagent's inherited model](/docs/en/sub-agents#choose-a-model) or the [lead's model for a teammate](/docs/en/agent-teams#specify-teammates-and-models) rather than failing the request. In interactive sessions, Claude Code warns you when it substitutes a subagent's model, by this fallback or by the newest-permitted-version substitution above, naming the requested and substituted models; it doesn't report a teammate's fallback. Where the newest-permitted-version substitution above operates, a blocked family alias follows it instead; before v2.1.222, an alias fell back like any other blocked value on every provider * **Skill or command override**: Claude Code ignores the override, including a blocked family alias, and the skill or command runs on the session model. A skill or command that [runs in a subagent](/docs/en/skills#run-skills-in-a-subagent) follows the subagent behavior above instead * **`advisorModel` setting**: the advisor is disabled for the session -* **`--advisor` flag**: Claude Code exits with an error at launch +* **`--advisor` flag**: Claude Code exits with an error at launch. In a [background session](/docs/en/agent-view), it starts the session without the advisor instead of exiting Claude Code hides excluded models from the `/model` picker. A full model ID in the list that has no built-in picker row, such as an older version that the list pins, appears in the `/model` picker as its own labeled row. Before v2.1.199, such an ID was selectable only by typing `/model <id>`.
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* **Main session model**: `/model`, the `--model` flag, the `ANTHROPIC_MODEL` environment variable, the `model` setting, and the model restored when [resuming a session](#setting-your-model) * **Alias resolution**: the `ANTHROPIC_DEFAULT_OPUS_MODEL`, `ANTHROPIC_DEFAULT_SONNET_MODEL`, `ANTHROPIC_DEFAULT_HAIKU_MODEL`, and `ANTHROPIC_DEFAULT_FABLE_MODEL` environment variables cannot redirect an allowed alias to a model outside the list * **Fast mode**: `/fast` refuses to toggle when it would implicitly switch to an Opus model outside the list, with the message "is not in your organization's allowed models" -* **Subagent and teammate models**: the `model` field in [subagent](/docs/en/sub-agents#choose-a-model) frontmatter, the Agent tool's `model` parameter, [agent team](/docs/en/agent-teams#specify-teammates-and-models) teammate models including the `teammateDefaultModel` setting, `CLAUDE_CODE_SUBAGENT_MODEL`, and, on v2.1.197 and earlier, the model picker in the `/agents` wizard  +* **Subagent and teammate models**: the `model` field in [subagent](/docs/en/sub-agents#choose-a-model) frontmatter, the Agent tool's `model` parameter, [agent team](/docs/en/agent-teams#specify-teammates-and-models) teammate models, `CLAUDE_CODE_SUBAGENT_MODEL`, and, on v2.1.197 and earlier, the model picker in the `/agents` wizard  * **Skill and command models**: the `model` frontmatter in [skills and commands](/docs/en/skills) * **Advisor model**: the configured [`advisorModel`](/docs/en/advisor) setting and the `--advisor` flag * **Background agent model**: the model selected in the [dispatch picker](/docs/en/agent-view)
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* **`/model`**: Claude Code rejects the switch with an error * **`--model` flag, `ANTHROPIC_MODEL`, or the `model` setting**: Claude Code replaces the value at startup with a warning naming both the requested and substituted models, and the session starts on the default model -* **Subagent or teammate override**: Claude Code falls back to the [subagent's inherited model](/docs/en/sub-agents#choose-a-model) or the [default teammate model](/docs/en/agent-teams#specify-teammates-and-models) rather than failing the request. In interactive sessions, Claude Code warns you when it substitutes a subagent's model, by this fallback or by the newest-permitted-version substitution above, naming the requested and substituted models; it doesn't report a teammate's fallback. When the blocked value is the **Default teammate model** setting itself, Claude Code runs the teammate on your provider's default Opus model, or on the lead's model when the allowlist blocks that too. Where the newest-permitted-version substitution above operates, a blocked family alias follows it instead; before v2.1.222, an alias fell back like any other blocked value on every provider +* **Subagent or teammate override**: Claude Code falls back to the [subagent's inherited model](/docs/en/sub-agents#choose-a-model) or the [lead's model for a teammate](/docs/en/agent-teams#specify-teammates-and-models) rather than failing the request. In interactive sessions, Claude Code warns you when it substitutes a subagent's model, by this fallback or by the newest-permitted-version substitution above, naming the requested and substituted models; it doesn't report a teammate's fallback. Where the newest-permitted-version substitution above operates, a blocked family alias follows it instead; before v2.1.222, an alias fell back like any other blocked value on every provider * **Skill or command override**: Claude Code ignores the override, including a blocked family alias, and the skill or command runs on the session model. A skill or command that [runs in a subagent](/docs/en/skills#run-skills-in-a-subagent) follows the subagent behavior above instead * **`advisorModel` setting**: the advisor is disabled for the session * **`--advisor` flag**: Claude Code exits with an error at launch
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Claude Code rejects an unrecognized string with `Model "<name>" is not a recognized model id.` and the session keeps its current model, instead of saving the string and failing on the next request. See [the error reference](/docs/en/errors#model-is-not-a-recognized-model-id) for recovery steps. -The check runs only on the Anthropic API. On Amazon Bedrock, Google Cloud's Agent Platform, Microsoft Foundry, [Claude Platform on AWS](/docs/en/claude-platform-on-aws), and behind an [LLM gateway](/docs/en/llm-gateway) or a custom `ANTHROPIC_BASE_URL`, your provider or gateway defines the model names, so Claude Code passes any string through without checking it. The check also doesn't cover the `--model` flag, the `ANTHROPIC_MODEL` environment variable, or the `model` setting; a mistyped value there produces [There's an issue with the selected model](/docs/en/errors#theres-an-issue-with-the-selected-model) on the first request instead. +The check runs only on the Anthropic API. On Amazon Bedrock, Google Cloud's Agent Platform, Microsoft Foundry, [Claude Platform on AWS](/docs/en/claude-platform-on-aws), and behind an [LLM gateway](/docs/en/llm-gateway) or a custom `ANTHROPIC_BASE_URL`, your provider or gateway defines the model names, so Claude Code passes any string through without checking it. The check also doesn't cover the `--model` flag, the `ANTHROPIC_MODEL` environment variable, or the `model` setting; a mistyped value there produces [There's an issue with the selected model](/docs/en/errors#theres-an-issue-with-the-selected-model) on the first request instead. Claude Code can still write the [unrecognized-model diagnostic line](/docs/en/errors#unrecognized-model-id-on-a-request) at request time, on every provider. When the requested model has a scheduled retirement date or is automatically remapped to a newer version, Claude Code shows a warning that names the requested model. Interactive sessions show it as a startup notice. From v2.1.182, the same warning is written to stderr in [non-interactive mode](/docs/en/headless) when using the default text output format. The check also covers a `model` set in [subagent frontmatter](/docs/en/sub-agents). The stderr warning is suppressed for `--output-format json` and `stream-json`; read the actual model from the `modelUsage` field of the [result message](/docs/en/headless#get-structured-output) instead.
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``` Keys must be Anthropic model IDs as listed in the [Models overview](https://platform.claude.com/docs/en/about-claude/models/overview). For dated model IDs, include the date suffix exactly as it appears there. Unknown keys are ignored. + +To stop the `[claude-code:unrecognized_model]` [diagnostic line](/docs/en/errors#unrecognized-model-id-on-a-request) for an ID such as a gateway alias, add an entry with that ID as its value. Overrides replace the built-in model IDs that back each entry in the `/model` picker. On Amazon Bedrock, `modelOverrides` entries take precedence over any inference profiles that Claude Code discovers automatically at startup. Claude Code passes values that are already provider-native, such as Amazon Bedrock inference profile ARNs or Microsoft Foundry deployment names, to the provider as-is.
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To get the most from Fable 5: -* **Describe the outcome, not the steps**: hand it the result you want and let it plan the path. To keep it working until that outcome holds, [set a goal](/docs/en/goal). +* **Describe the outcome, not the steps**: hand it the result you want and let it plan the path. To keep it working toward that outcome, [set a goal](/docs/en/goal). * **Hand it ambiguous problems**: root-cause investigations, outage debugging, and architecture decisions are where the extra investigation and verification pay off. * **Skip the verification reminders**: it verifies its own work with less prompting, so reminders to test or check are usually unnecessary. * **Size up larger tasks**: give it work you would normally break into pieces. It holds long sessions without losing the thread.
model-config First recorded · 788 lines, first recorded
# Model configuration ## Available models ### Model aliases ### Work with Fable 5 #### Fable 5 and usage credits ### Setting your model ## Restrict model selection ### Surface coverage ### Default model behavior ### Enforce the allowlist for the Default model ### Control the model users run on ### Merge behavior ### Mantle model IDs ### Organization model restrictions ## Organization default model ## Organization effort limits ## Special model behavior ### `default` model setting ### `opusplan` model setting ### Fallback model chains ### Automatic model fallback #### Check what triggered fallback #### Ask before switching #### Enable fallback on Bedrock, Agent Platform, and Foundry #### Security research and biology workloads ### Adjust effort level #### Choose an effort level #### Use ultrathink for one-off deep reasoning #### Set the effort level #### Adaptive reasoning and fixed thinking budgets ### Extended thinking ### Extended context #### Sonnet 5 context window ## Context window and auto-compaction ### Set the auto-compact window ### Default auto-compact thresholds ### Correct the window for a gateway or custom model ID ## Checking your current model ## Add a custom model option ## Environment variables ### Pin models for third-party deployments ### Customize pinned model display and capabilities ### Override model IDs per version ### Prompt caching configuration
The first capture of this source. The page was already there, and this is what it said.
# Model configuration
> Configure which model Claude Code uses, effort levels, extended context, and the auto-compact window
## Available models
For the `model` setting in Claude Code, you can configure either:
* A **model alias**
* A **model name**
* Anthropic API: a full **[model name](https://platform.claude.com/docs/en/about-claude/models/overview)**
* Amazon Bedrock: an inference profile ARN
* Microsoft Foundry: a deployment name
* Google Cloud's Agent Platform: a version name
For guidance on which model and effort level fit different kinds of work, see [Choosing a Claude model and effort level in Claude Code](https://claude.com/blog/claude-model-and-effort-level-in-claude-code) on the blog.
<Note>
`ANTHROPIC_BASE_URL` changes where requests are sent, not which model answers them. To route Claude through an LLM gateway, see [LLM gateways](/docs/en/llm-gateway).
</Note>
### Model aliases
Use a model alias to select model settings without remembering exact version numbers:
| Model alias | Behavior |
| ---------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **`default`** | Special value that clears any model override and reverts to the recommended model for your account type, or to the [organization default model](#organization-default-model) when an admin has set one. Not itself a model alias |
| **`best`** | Uses Fable 5 where your organization has access to it, otherwise the latest Opus model |
| **`fable`** | Uses Claude Fable 5 for your hardest and longest-running tasks |
| **`sonnet`** | Uses the latest Sonnet model for daily coding tasks |
| **`opus`** | Uses the latest Opus model for complex reasoning tasks |
| **`haiku`** | Uses the fast and efficient Haiku model for simple tasks |
| **`sonnet[1m]`** | Uses Sonnet with a [1 million token context window](https://platform.claude.com/docs/en/build-with-claude/context-windows#context-window-sizes-by-model) for long sessions. No effect when `sonnet` already resolves to Sonnet 5 with its native 1M window; behind an [LLM gateway](/docs/en/llm-gateway), selects the 1M window for Sonnet 5 |
| **`opus[1m]`** | Uses Opus with a [1 million token context window](https://platform.claude.com/docs/en/build-with-claude/context-windows#context-window-sizes-by-model) for long sessions |
| **`opusplan`** | Special mode that uses `opus` during plan mode, then switches to `sonnet` for execution |
The version that the `opus` and `sonnet` aliases resolve to depends on the provider:
| Provider | `opus` | `sonnet` |
| :--------------------------------------------------- | :------- | :--------- |
| Anthropic API | Opus 5 | Sonnet 5 |
| [Claude Platform on AWS](/docs/en/claude-platform-on-aws) | Opus 5 | Sonnet 4.6 |
| Amazon Bedrock, Google Cloud's Agent Platform | Opus 5 | Sonnet 4.5 |
| Microsoft Foundry | Opus 4.6 | Sonnet 4.5 |
Where 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`.
Before 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.
Aliases point to the recommended version for your provider and update over time. To pin to a specific version, use the full model name, for example `claude-opus-5`, or set the corresponding environment variable like `ANTHROPIC_DEFAULT_OPUS_MODEL`.
<Note>
Opus 5 requires Claude Code v2.1.219 or later. Sonnet 5 requires v2.1.197 or later. Opus 4.8 requires v2.1.154 or later. Run `claude update` to upgrade.
</Note>
### Work with Fable 5
[Claude Fable 5](https://platform.claude.com/docs/en/about-claude/models/introducing-claude-fable-5-and-claude-mythos-5) is the most capable model in Claude Code, suited to tasks larger than a single sitting. It sustains long autonomous sessions, investigates before acting, and verifies its work more often than smaller models.
Fable 5 is not the default model. Select it with `/model fable`. Requests that its safety classifiers flag, most often in cybersecurity and biology domains, trigger [automatic model fallback](#automatic-model-fallback).
To get the most from Fable 5:
* **Describe the outcome, not the steps**: hand it the result you want and let it plan the path. To keep it working until that outcome holds, [set a goal](/docs/en/goal).
* **Hand it ambiguous problems**: root-cause investigations, outage debugging, and architecture decisions are where the extra investigation and verification pay off.
* **Skip the verification reminders**: it verifies its own work with less prompting, so reminders to test or check are usually unnecessary.
* **Size up larger tasks**: give it work you would normally break into pieces. It holds long sessions without losing the thread.
<Note>
Fable 5 requires Claude Code v2.1.170 or later. Older versions do not show Fable 5 in the model picker and cannot select it. Run `claude update` to upgrade. Fable 5 is not available under [zero data retention](/docs/en/zero-data-retention), where the `/model` picker either omits it or shows it disabled.
</Note>
On the Anthropic API, the `/model` picker lists Fable 5 only after the server reports it available for your organization. When you type `/model fable`, Claude Code checks availability with the server directly, so the selection can succeed before the picker lists the entry.
#### Fable 5 and usage credits
Depending on your plan and seat tier, Fable 5 usage can bill to [usage credits](https://support.claude.com/en/articles/12429409-extra-usage-for-paid-claude-plans) instead of drawing on your plan's included limits. When it does, the `/model` picker shows "Requires usage credits" on the Fable 5 row. To manage usage credits, see [Add usage credits to your subscription](/docs/en/costs#add-usage-credits-to-your-subscription).
In interactive sessions, Claude Code shows a consent prompt before a Fable 5 request bills usage credits. Members of Enterprise plans with organization billing don't see the prompt. You can continue on Fable 5 using usage credits or switch to your default model. You can also dismiss the prompt:
* In the `/model` picker, you keep your current model.
* Mid-session, Claude Code continues the turn on your default model.
After you choose to continue on Fable 5 using usage credits, Claude Code doesn't show the prompt again.
In [non-interactive mode](/docs/en/headless) with the `-p` flag and through the Agent SDK, Claude Code never shows the consent prompt. When a Fable 5 request there would bill to usage credits, Claude Code bills it without asking.
### Setting your model
You can configure your model in several ways, listed in order of priority:
1. **During session**: use `/model <alias|name>` to switch immediately, or run `/model` with no argument to open the picker. The picker asks for confirmation when the conversation has prior output, since the next response re-reads the full history without cached context
2. **At startup**: launch with `claude --model <alias|name>`
3. **Environment variable**: set `ANTHROPIC_MODEL=<alias|name>`
4. **Settings**: configure permanently in your settings file using the `model` field
As of v2.1.153, `/model` saves your choice as the default for new sessions by writing the `model` field in your user settings. In the picker:
* `Enter`: switch model and save as your default
* `s`: switch model for this session only
Typing `/model <name>` directly behaves like `Enter`. A model set with `/model` in [non-interactive mode](/docs/en/headless), with the `-p` flag, applies to the current session only and isn't saved as your default. Project and managed settings still take precedence and reapply on the next launch. An [organization default model](#organization-default-model) that your admin has configured to override user selection also reapplies on the next launch.
In v2.1.144 through v2.1.152, `/model` applied to the current session only and `d` in the picker saved a default.
The `--model` flag and `ANTHROPIC_MODEL` environment variable apply only to the session you launch with them. To run different models in different terminals at the same time, launch each one with its own `--model` flag rather than switching with `/model`.
Prices in the `/model` picker appear when Claude Code talks to the Anthropic API, directly or through an [LLM gateway](/docs/en/llm-gateway) that proxies it, and the price on a row is the price of the model that row selects. On [third-party providers](/docs/en/third-party-integrations) such as Amazon Bedrock and on the [Claude apps gateway](/docs/en/claude-apps-gateway), your provider or gateway determines what you pay, so picker rows show no price. The price is a display label only; it doesn't affect which model a row selects or what your provider bills. Before v2.1.206, [Claude Platform on AWS](/docs/en/claude-platform-on-aws) and gateway sessions showed Anthropic list prices, and a row could show the price of a different model than the one it selected.
Resumed sessions started with `claude --resume`, `--continue`, or the `/resume` picker keep the model they were using when the transcript was saved, regardless of the current `model` setting. If the restored model has been retired or is excluded by [`availableModels`](#restrict-model-selection), the session falls through to the normal precedence order. This prevents another session's `/model` choice from changing the model on resume. On providers that use provider-specific deployment IDs rather than Anthropic model IDs, such as Amazon Bedrock, Google Cloud's Agent Platform, and Microsoft Foundry, the transcript model isn't restored at all and the session resolves its model through the normal precedence order.
A model you pick for the new launch with `--model` or `ANTHROPIC_MODEL` still takes precedence over the restored model. As of v2.1.195, so does an [`ANTHROPIC_DEFAULT_OPUS_MODEL`](#environment-variables) family variable.
When 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; the key-level enumeration is under [Settings precedence](/docs/en/settings#settings-precedence).
When 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:
* a model alias
* an entry from the `/model` picker
* any name that starts with `claude-`
* a value you configured yourself as a [custom model option](#add-a-custom-model-option) or in [`modelOverrides`](#override-model-ids-per-version)
Claude Code rejects an unrecognized string with `Model "<name>" is not a recognized model id.` and the session keeps its current model, instead of saving the string and failing on the next request. See [the error reference](/docs/en/errors#model-is-not-a-recognized-model-id) for recovery steps.
The check runs only on the Anthropic API. On Amazon Bedrock, Google Cloud's Agent Platform, Microsoft Foundry, [Claude Platform on AWS](/docs/en/claude-platform-on-aws), and behind an [LLM gateway](/docs/en/llm-gateway) or a custom `ANTHROPIC_BASE_URL`, your provider or gateway defines the model names, so Claude Code passes any string through without checking it. The check also doesn't cover the `--model` flag, the `ANTHROPIC_MODEL` environment variable, or the `model` setting; a mistyped value there produces [There's an issue with the selected model](/docs/en/errors#theres-an-issue-with-the-selected-model) on the first request instead.
When the requested model has a scheduled retirement date or is automatically remapped to a newer version, Claude Code shows a warning that names the requested model. Interactive sessions show it as a startup notice. From v2.1.182, the same warning is written to stderr in [non-interactive mode](/docs/en/headless) when using the default text output format. The check also covers a `model` set in [subagent frontmatter](/docs/en/sub-agents). The stderr warning is suppressed for `--output-format json` and `stream-json`; read the actual model from the `modelUsage` field of the [result message](/docs/en/headless#get-structured-output) instead.
For example, start a session on Opus:
```bash theme={null}
claude --model opus
```
Then switch models from within the session:
```text theme={null}
/model sonnet
```
Example settings file:
```json theme={null}
{
"permissions": {
"allow": ["Bash(npm run lint)"]
},
"model": "opus"
}
```
## Restrict model selection
Enterprise administrators can use `availableModels` in [managed or policy settings](/docs/en/settings#settings-files) to restrict which models users can select. Entries match a model family such as `sonnet`, a version prefix such as `claude-sonnet-4-5`, or a full model ID such as `claude-sonnet-4-5-20250929`.
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; the key-level enumeration is under [Settings precedence](/docs/en/settings#settings-precedence).
When `availableModels` is set, the allowlist applies everywhere a user can specify a model:
* **Main session model**: `/model`, the `--model` flag, the `ANTHROPIC_MODEL` environment variable, the `model` setting, and the model restored when [resuming a session](#setting-your-model)
* **Alias resolution**: the `ANTHROPIC_DEFAULT_OPUS_MODEL`, `ANTHROPIC_DEFAULT_SONNET_MODEL`, `ANTHROPIC_DEFAULT_HAIKU_MODEL`, and `ANTHROPIC_DEFAULT_FABLE_MODEL` environment variables cannot redirect an allowed alias to a model outside the list
* **Fast mode**: `/fast` refuses to toggle when it would implicitly switch to an Opus model outside the list, with the message "is not in your organization's allowed models"
* **Subagent and teammate models**: the `model` field in [subagent](/docs/en/sub-agents#choose-a-model) frontmatter, the Agent tool's `model` parameter, [agent team](/docs/en/agent-teams#specify-teammates-and-models) teammate models including the `teammateDefaultModel` setting, `CLAUDE_CODE_SUBAGENT_MODEL`, and, on v2.1.197 and earlier, the model picker in the `/agents` wizard 
* **Skill and command models**: the `model` frontmatter in [skills and commands](/docs/en/skills)
* **Advisor model**: the configured [`advisorModel`](/docs/en/advisor) setting and the `--advisor` flag
* **Background agent model**: the model selected in the [dispatch picker](/docs/en/agent-view)
On the Anthropic API and [Claude Platform on AWS](/docs/en/claude-platform-on-aws), a model family alias, `opus`, `sonnet`, `haiku`, or `fable`, resolves to the newest version of its family that the allowlist permits. When the allowlist pins specific versions, for example `["sonnet", "claude-opus-4-6"]`, both `/model opus` and `--model opus` select Claude Opus 4.6, the newest permitted Opus, and show a notice naming both the requested and substituted models. Before v2.1.205, an alias whose newest released version was outside the list was rejected or replaced like any other blocked selection, even when the list permitted an older version.
The substitution needs a permitted version to land on: when the allowlist permits no version of the alias's family, the alias follows the rejection and replacement behavior below like any other blocked value.
Claude Code handles any other blocked selection according to where the model was set:
* **`/model`**: Claude Code rejects the switch with an error
* **`--model` flag, `ANTHROPIC_MODEL`, or the `model` setting**: Claude Code replaces the value at startup with a warning naming both the requested and substituted models, and the session starts on the default model
* **Subagent or teammate override**: Claude Code falls back to the [subagent's inherited model](/docs/en/sub-agents#choose-a-model) or the [default teammate model](/docs/en/agent-teams#specify-teammates-and-models) rather than failing the request. In interactive sessions, Claude Code warns you when it substitutes a subagent's model, by this fallback or by the newest-permitted-version substitution above, naming the requested and substituted models; it doesn't report a teammate's fallback. When the blocked value is the **Default teammate model** setting itself, Claude Code runs the teammate on your provider's default Opus model, or on the lead's model when the allowlist blocks that too. Where the newest-permitted-version substitution above operates, a blocked family alias follows it instead; before v2.1.222, an alias fell back like any other blocked value on every provider
* **Skill or command override**: Claude Code ignores the override, including a blocked family alias, and the skill or command runs on the session model. A skill or command that [runs in a subagent](/docs/en/skills#run-skills-in-a-subagent) follows the subagent behavior above instead
* **`advisorModel` setting**: the advisor is disabled for the session
* **`--advisor` flag**: Claude Code exits with an error at launch
Claude Code hides excluded models from the `/model` picker. A full model ID in the list that has no built-in picker row, such as an older version that the list pins, appears in the `/model` picker as its own labeled row. Before v2.1.199, such an ID was selectable only by typing `/model <id>`.
Model changes that Claude Code makes on your behalf are checked the same way:
* **[Fallback model chains](#fallback-model-chains)**: entries outside the allowlist are dropped
* **Plan-mode upgrades**: on the Anthropic API and Claude Platform on AWS, an upgrade such as [`opusplan`](#opusplan-model-setting) to an excluded model uses the newest permitted version of the upgrade family. On providers with provider-specific model IDs, and when no version is permitted, the upgrade is skipped and planning continues on the session's model
* **[Automatic model fallback](#automatic-model-fallback)**: a fallback whose target is excluded does not run, so the flagged request ends with a refusal instead
* **[Auto mode classifier](/docs/en/permission-modes#eliminate-prompts-with-auto-mode)**: the classifier's Claude Sonnet 5 default applies only when the allowlist permits Sonnet 5. When it's excluded, the classifier runs on the session's model, which the allowlist already governs, or on an Opus model when the session runs on [Fable 5](#work-with-fable-5). On providers other than the Anthropic API, that Opus fallback runs on the provider's default Opus model without consulting the allowlist. Requires Claude Code v2.1.210 or later
* **[Fast mode](/docs/en/fast-mode)**: enabling fast mode is refused when the model the session would run on afterward is outside the allowlist
```json theme={null}
{
"availableModels": ["sonnet", "haiku"]
}
```
### Surface coverage
Every surface enforces the allowlist it receives. Which delivery mechanism reaches each surface differs:
| Delivery mechanism | CLI and IDE | Desktop local sessions | Web, mobile, and cloud sessions | Agent SDK and non-interactive | Cowork |
| :---------------------------------------------------------------------------- | :---------- | :--------------------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :---------------------------- | :---------------------- |
| [Server-managed settings](/docs/en/server-managed-settings) from the admin console | Enforced | Enforced | Enforced | Enforced | Not delivered |
| [MDM or managed settings files](/docs/en/settings#settings-files) | Enforced | Enforced | Not delivered in Anthropic-hosted environments; in [self-hosted environments](/docs/en/self-hosted-environments), enforced from the runner image when server-managed settings deliver no keys | Enforced | Enforced where deployed |
* Cloud sessions, on [Claude Code on the web](/docs/en/claude-code-on-the-web) or in the Desktop app, run on Anthropic-managed VMs by default: settings deployed to your device do not reach them, so deliver the allowlist through server-managed settings. Sessions your organization routes to a [self-hosted environment](/docs/en/self-hosted-environments) run on your own compute and fall back to the managed settings file in the runner image when your organization delivers no server-managed settings; when both exist, the server-managed payload takes precedence, with the per-key `env` merge exception described in [settings precedence](/docs/en/server-managed-settings#settings-precedence). A mid-session model switch in a cloud session is rejected when the requested model is excluded by the allowlist. Server-side rejection at session creation applies to [organization model restrictions](#organization-model-restrictions), not the `availableModels` settings key.
* Cowork, the agentic-work tab in the Claude Desktop app, is not a Claude Code surface and does not receive server-managed settings by design. A managed settings file applies to Cowork sessions when it is present where the session runs; remote Cowork sessions run on Anthropic-managed VMs, where a device-deployed file is not present.
* Sessions on [third-party providers](/docs/en/server-managed-settings#platform-availability) such as Amazon Bedrock, Google Cloud's Agent Platform, Microsoft Foundry, and [Claude Platform on AWS](/docs/en/claude-platform-on-aws) do not receive server-managed settings, so deliver the allowlist through MDM or managed settings files there.
* Server-managed delivery also requires the session to authenticate with an organization login or a directly configured API key. Fleets that generate keys only through an [`apiKeyHelper`](/docs/en/settings#available-settings) script should deliver the allowlist through MDM or managed settings files.
* The Desktop Code tab also hosts [SSH sessions](/docs/en/desktop#ssh-sessions), which read the managed settings file from the remote host they run on. See [Desktop managed settings](/docs/en/desktop#managed-settings).
* The model pickers on claude.ai and in the Desktop app hide or grey out models excluded by your organization's allowlist. The picker state is a convenience for users; enforcement happens in the session.
### Default model behavior
The Default option in the model picker is not affected by `availableModels` unless [`enforceAvailableModels`](#enforce-the-allowlist-for-the-default-model) is also set. On its own, `availableModels` leaves Default available, resolving to the system's [runtime default](#default-model-setting) for the account. If that default is a model you intend to restrict, set `enforceAvailableModels` as well.
An empty `availableModels` array never engages the Default-model enforcement: with `availableModels: []`, named model selections are blocked but the Default model for the account type remains usable regardless of `enforceAvailableModels`.
### Enforce the allowlist for the Default model
Set `enforceAvailableModels: true` alongside a non-empty `availableModels` in managed settings to extend the allowlist to the Default option. This requires Claude Code v2.1.175 or later.
```json theme={null}
{
"availableModels": ["sonnet", "haiku"],
"enforceAvailableModels": true
}
```
The Default option resolves to the account-type default, or to the [organization default model](#organization-default-model) when an admin has set one. When that model is not in the allowlist, the Default option instead resolves to the first `availableModels` entry that names an allowed, available model, and the `/model` picker's Default row shows that model. This applies everywhere the default is reached: session startup, selecting Default in `/model`, the `"default"` keyword in [fallback model chains](#fallback-model-chains), and the fallback used when an excluded selection is dropped.
`enforceAvailableModels` has no effect when `availableModels` is unset or empty: with `availableModels: []`, the Default model for the account type remains usable, so the setting cannot lock users out of every model. When `availableModels` is non-empty but no entry resolves to an allowed and available model, enforcement is skipped and Default resolves to the account-type default, with a warning visible only under `--debug`. Keep at least one guaranteed-available entry in the list to avoid this.
Deploy both keys in the [highest-precedence managed source](/docs/en/settings#precedence-within-the-managed-tier): these keys don't merge across managed sources, so a pair placed in a managed settings file is ignored when the admin console delivers any settings.
### Control the model users run on
The `model` setting is an initial selection, not enforcement. It sets which model is active when a session starts, but users can still open `/model` and pick Default, which resolves to the system's [runtime default](#default-model-setting) regardless of what `model` is set to, unless [`enforceAvailableModels`](#enforce-the-allowlist-for-the-default-model) redirects it.
To fully control the model experience, combine these settings:
* **`availableModels`**: restricts which named models users can switch to
* **`enforceAvailableModels`**: extends the `availableModels` allowlist to the Default option, so Default cannot resolve to a model outside the list
* **`model`**: sets the initial model selection when a session starts
* **`ANTHROPIC_DEFAULT_SONNET_MODEL`** / **`ANTHROPIC_DEFAULT_OPUS_MODEL`** / **`ANTHROPIC_DEFAULT_HAIKU_MODEL`** / **`ANTHROPIC_DEFAULT_FABLE_MODEL`**: control what the Default option and the `sonnet`, `opus`, `haiku`, and `fable` aliases resolve to
This example starts users on Sonnet 4.5, limits the picker to Sonnet and Haiku, and ensures Default resolves to a model on the allowlist rather than the tier default:
```json theme={null}
{
"model": "claude-sonnet-4-5",
"availableModels": ["claude-sonnet-4-5", "haiku"],
"enforceAvailableModels": true,
"env": {
"ANTHROPIC_DEFAULT_SONNET_MODEL": "claude-sonnet-4-5"
}
}
```
Without `enforceAvailableModels` or the `env` block, a user who selects Default in the picker would get the latest release for their tier, bypassing the version pin in `model` and `availableModels`. The two settings cover different scopes: `enforceAvailableModels` makes Default obey the allowlist, while the `env` block pins which version a permitted alias such as `sonnet` resolves to. Use `enforceAvailableModels` alone when restricting model families is enough; add the `env` block when you also need to pin a specific version.
### Merge behavior
When the [highest-precedence managed settings source](/docs/en/server-managed-settings#settings-precedence) defines `availableModels`, that list alone applies, apart from a [host platform that supplies its own](/docs/en/settings#exceptions-to-managed-settings-precedence): entries in user, project, or local settings cannot extend it, and `availableModels` doesn't merge across admin-deployed managed sources, so a list deployed in a managed settings file is ignored when server-managed settings deliver any keys. Otherwise, lists from user, project, and local settings are [concatenated and deduplicated](/docs/en/settings#settings-precedence) like other array settings. As of Claude Code v2.1.175, the managed list replaces lower-precedence entries; earlier versions merge them.
Within the effective list, an entry naming a specific model in a family, whether a version prefix or a full model ID, disables that family's wildcard entry: `["sonnet", "claude-sonnet-4-5"]` allows only Sonnet 4.5 versions, not every Sonnet model.
### Mantle model IDs
When the [Amazon Bedrock Mantle endpoint](/docs/en/amazon-bedrock#use-the-mantle-endpoint) is enabled, entries in `availableModels` that start with `anthropic.` are added to the `/model` picker as custom options and routed to the Mantle endpoint. This is an exception to the alias matching described in [Pin models for third-party deployments](#pin-models-for-third-party-deployments). The setting still restricts the picker to listed entries, and a Mantle ID embeds a family name, so it counts as a specific entry and disables that family's wildcard: alongside any Mantle IDs, list the version prefixes or full IDs you want to keep selectable. See [Merge behavior](#merge-behavior).
### Organization model restrictions
Organization admins on Claude Enterprise plans restrict which models members can run by disabling individual models in the claude.ai admin console. This restriction is delivered with the account's entitlements when Claude Code authenticates, separate from any `availableModels` list in settings, and the server enforces the same restriction independently when a session is created. Requires Claude Code v2.1.187 or later.
The restriction applies when a member signs in or uses their own API key. Organization-scoped credentials, such as organization service keys, are not tied to a user, so the restriction does not apply to them.
The Claude Console has no model restriction control. Organizations without a Claude Enterprise plan, including those whose members authenticate through the Anthropic API, restrict models with [`availableModels`](#restrict-model-selection) in [managed settings](/docs/en/settings#settings-files) instead, adding [`enforceAvailableModels`](#enforce-the-allowlist-for-the-default-model) to cover the Default option. These settings are enforced by Claude Code itself, not by the server.
A restricted model is hidden from the `/model` picker. Selecting it by name with `--model`, the `ANTHROPIC_MODEL` environment variable, or the `model` setting shows the notice `Model "<name>" is restricted by your organization's settings. Using <model> instead.` and the session starts on an allowed model. Typing `/model <name>` for a restricted model is rejected with `Model '<name>' is restricted by your organization's settings. Run /model to choose a different model.` and the session keeps its current model.
A [model family alias](#restrict-model-selection) such as `opus` resolves to the newest version of its family that the organization permits, with the same substitution notice. `/model <alias>` is rejected only when every version of its family is restricted; an alias set with `--model`, `ANTHROPIC_MODEL`, or the `model` setting is still replaced at startup in that case. Before v2.1.205, a family alias was substituted or rejected based on its newest released version alone, even when an older version was allowed.
Restrictions apply org-wide or per role:
* Disabling a model at the organization level removes it for every member.
* Role-level access grants different models to different custom roles, and a member who holds several roles can use any model that one of their roles grants.
* Haiku models are always available and can't be disabled, so every member keeps at least one usable model.
* An access change takes effect on new requests within about a minute; the `/model` picker reflects it the next time a session starts.
Both restrictions apply together: a model is selectable only when it is permitted by `availableModels` and not restricted by the organization. Organization restrictions reach sessions on the Anthropic API and [LLM gateway](/docs/en/llm-gateway) deployments only; on any other provider, use `availableModels` instead.
## Organization default model
Organization admins on Claude Enterprise plans can set a default model for Claude Code members from the claude.ai admin console, for the whole organization or per custom role. When one is set, the Default option resolves to that model instead of the [account-type default](#default-model-setting). Requires Claude Code v2.1.196 or later.
The Default row in the `/model` picker shows the organization default's name with the label Org default. The label reads Org default whether the admin set the default for the whole organization or for your role. A role default covers members of that custom role and takes precedence over the organization-wide default; when several of your roles set different defaults, the most capable model applies.
The organization default is a starting point, not a restriction, and any other model selection takes precedence over it:
Cut at 300 lines.