Speed up responses with fast mode changedfast-mode
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1414
1515What to know:
1616
17* Use `/fast` to toggle on fast mode in the Claude Code CLI. The [VS Code extension](/docs/en/vs-code) offers a **Toggle fast mode** command when the selected model supports fast mode. Claude Code saves that toggle to your [`fastMode` setting](#toggle-fast-mode).
17* Use `/fast` to toggle on fast mode in the Claude Code CLI. The [VS Code extension](/docs/en/vs-code.md) offers a **Toggle fast mode** command when the selected model supports fast mode. Claude Code saves that toggle to your [`fastMode` setting](#toggle-fast-mode).
1818* Fast mode pricing per MTok input/output is \$8/\$40 on Opus 5.5 and \$10/\$50 on Opus 5 and Opus 4.8.
1919* Available to Claude Code users on subscription plans (Pro/Max/Team/Enterprise) and on Claude Console. Team and Enterprise organizations need an Owner to enable it first, and Console organizations need access provisioned first, both described under [Requirements](#requirements).
2020* For Claude Code users on subscription plans (Pro/Max/Team/Enterprise), fast mode is available via usage credits only and not included in the subscription rate limits.
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2424In the CLI, toggle fast mode in either of these ways:
2525
2626* Run `/fast`, press Space to toggle on or off, then press Enter to confirm
27* Set `"fastMode": true` in your [user settings file](/docs/en/settings)
27* Set `"fastMode": true` in your [user settings file](/docs/en/settings.md)
2828
2929By default, fast mode you turn on in an interactive session persists across sessions. You can configure fast mode to reset each session. See [require per-session opt-in](#require-per-session-opt-in) for details.
3030
31Outside a [cloud session](#use-fast-mode-in-cloud-sessions), in [non-interactive mode](/docs/en/headless) with the `-p` flag, `/fast` works only in a session launched with fast mode in its [`--settings`](/docs/en/cli-reference#cli-flags) value, for example `claude -p --settings '{"fastMode": true}'`; the toggle then applies to that session only and isn't saved as your default. The `-p` form requires Claude Code v2.1.205 or later. Elsewhere in non-interactive mode, the command reports that fast mode isn't available.
31Outside a [cloud session](#use-fast-mode-in-cloud-sessions), in [non-interactive mode](/docs/en/headless.md) with the `-p` flag, `/fast` works only in a session launched with fast mode in its [`--settings`](/docs/en/cli-reference#cli-flags) value, for example `claude -p --settings '{"fastMode": true}'`; the toggle then applies to that session only and isn't saved as your default. The `-p` form requires Claude Code v2.1.205 or later. Elsewhere in non-interactive mode, the command reports that fast mode isn't available.
3232
3333You can run `/fast` while Claude is working, and Claude Code toggles fast mode without waiting for the turn to end. Claude Code finishes the running turn at its original speed, so the speed change takes effect from your next turn. If your current model doesn't support fast mode, turning it on also switches your model, and Claude Code uses the new model from its next request in that turn.
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5252* **Switch away**: when you switch to a model that doesn't support fast mode, Claude Code turns fast mode off. This includes Opus 4.7; before v2.1.221, fast mode stayed on after a switch to Opus 4.7 and the API rejected the requests.
5353* **Switch back**: switching back to a supported Opus model turns fast mode on again when your saved fast mode preference is on, the same preference a new session starts from by default. A model switch never turns fast mode on for a session whose saved preference is off, and with [per-session opt-in](#require-per-session-opt-in) configured, switching back doesn't turn it on either; run `/fast` to re-enable it.
5454
55Whenever a model switch turns fast mode on or off, Claude Code shows a `Fast mode ON` or `Fast mode OFF` confirmation, and the `↯` icon appears while fast mode is on. This holds whether you switch with `/model`, with [`/config model=<model>`](/docs/en/settings), or from a device connected through [Remote Control](/docs/en/remote-control).
55Whenever a model switch turns fast mode on or off, Claude Code shows a `Fast mode ON` or `Fast mode OFF` confirmation, and the `↯` icon appears while fast mode is on. This holds whether you switch with `/model`, with [`/config model=<model>`](/docs/en/settings), or from a device connected through [Remote Control](/docs/en/remote-control.md).
5656
5757Claude Code resends the session's fast mode status to devices connected through Remote Control after a model switch, a reconnection, or a failed [availability check](#use-fast-mode-behind-proxies-and-llm-gateways).
5858
5959### Use fast mode in cloud sessions
6060
61Fast mode works in [cloud sessions](/docs/en/claude-code-on-the-web) when it's available on your account, whether the session runs on Anthropic-managed infrastructure or a [self-hosted runner](/docs/en/self-hosted-environments). Requires Claude Code v2.1.271 or later in the session's environment.
61Fast mode works in [cloud sessions](/docs/en/claude-code-on-the-web.md) when it's available on your account, whether the session runs on Anthropic-managed infrastructure or a [self-hosted runner](/docs/en/self-hosted-environments). Requires Claude Code v2.1.271 or later in the session's environment.
6262
6363Type `/fast on` in the session to turn fast mode on. It stays on for that session only and isn't saved as your default. The [requirements](#requirements) apply in cloud sessions too.
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7676
7777Fast mode pricing is flat across the full 1M token context window. For the standard Opus rate to compare against, see the [Claude pricing reference](https://platform.claude.com/docs/en/about-claude/pricing).
7878
79The first time you enable fast mode in a conversation, you pay the full fast mode uncached input token price for the entire conversation context. The deeper into a conversation you are, the more this costs, so the charge is smallest when you enable fast mode at the start. The cost applies once per conversation, so toggling fast mode off and on again later doesn't repeat it. For the mechanism, see [how fast mode interacts with the prompt cache](/docs/en/prompt-caching#turning-on-fast-mode).
79The first time you enable fast mode in a conversation, you pay the full fast mode uncached input token price for the entire conversation context. The deeper into a conversation you are, the more this costs, so the charge is smallest when you enable fast mode at the start. The cost applies once per conversation, so toggling fast mode off and on again later doesn't repeat it. For the mechanism, see [how fast mode interacts with the prompt cache](/docs/en/prompt-caching.md#turning-on-fast-mode).
8080
8181### See where fast mode spend appears
8282
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8383You see fast mode spend in a different place depending on how you signed in, so first run [`/status`](/docs/en/commands) to check. If it shows a `Login method` row such as `Claude Max account`, you signed in with a Claude subscription. If it shows an `API key` row instead, your requests bill to a Claude Console organization.
8484
8585* **Pro and Max**: you pay for fast mode from your usage credits. Go to [**Settings > Usage**](https://claude.ai/settings/usage) on claude.ai, where the **Usage credits** section shows how much you've spent in usage credits this month. That figure includes fast mode but doesn't break it out separately.
86* **Team and Enterprise**: your organization pays for your fast mode usage from its usage credits. To see your own usage-credits spend, run [`/usage`](/docs/en/costs#check-your-usage-credits-spend). For where your organization sees that spend, see [Claude for Teams and Enterprise](/docs/en/costs#claude-for-teams-and-enterprise).
86* **Team and Enterprise**: your organization pays for your fast mode usage from its usage credits. To see your own usage-credits spend, run [`/usage`](/docs/en/costs#check-your-usage-credits-spend). For where your organization sees that spend, see [Claude for Teams and Enterprise](/docs/en/costs.md#claude-for-teams-and-enterprise).
8787* **Claude Console**: your organization pays for fast mode with the rest of its API usage. On the Console [Usage](https://platform.claude.com/usage) and [Cost](https://platform.claude.com/cost) pages, select **Speed (Research Preview)** in the **Group by** menu to separate fast mode from standard-speed usage. You see that option only when the selected date range includes fast mode usage.
8888
8989## Decide when to use fast mode
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109109| **Fast mode** | Same model quality, lower latency, higher cost |
110110| **Lower effort level** | Less thinking time, faster responses, potentially lower quality on complex tasks |
111111
112You can combine both: use fast mode with a lower [effort level](/docs/en/model-config#adjust-effort-level) for maximum speed on straightforward tasks.
112You can combine both: use fast mode with a lower [effort level](/docs/en/model-config.md#adjust-effort-level) for maximum speed on straightforward tasks.
113113
114114## Requirements
115115
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116116Fast mode requires all of the following:
117117
118118* **Anthropic API or subscription only**: fast mode is available through the Anthropic Console API and for Claude subscription plans using usage credits. It is not available on Amazon Bedrock, Google Cloud's Agent Platform, Microsoft Foundry, or Claude Platform on AWS. Console organizations must also have [fast mode access provisioned](#enable-fast-mode-for-your-organization).
119* **Usage credits turned on for subscription plans**: on a Pro, Max, Team, or Enterprise plan, your account must have [usage credits](/docs/en/costs#add-usage-credits-to-your-subscription) turned on, which allows billing beyond your plan's included usage. Until they're on, `/fast` reports "Fast mode requires usage credits". How you turn them on depends on your plan:
119* **Usage credits turned on for subscription plans**: on a Pro, Max, Team, or Enterprise plan, your account must have [usage credits](/docs/en/costs.md#add-usage-credits-to-your-subscription) turned on, which allows billing beyond your plan's included usage. Until they're on, `/fast` reports "Fast mode requires usage credits". How you turn them on depends on your plan:
120120 * On Pro and Max, turn them on in the **Usage credits** section of [**Settings > Usage**](https://claude.ai/settings/usage) on claude.ai, or run `/usage-credits` to open that page.
121121 * On Team and Enterprise, a member with billing access turns them on for the organization at [**Organization settings > Usage**](https://claude.ai/admin-settings/usage), and a member without it runs `/usage-credits` to send the organization's admins a request.
122122
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132132> Four organization settings can block turning fast mode on with `/fast`:
133133>
134134> * **Fast mode not enabled**: if fast mode hasn't been enabled for your organization, turning fast mode on with `/fast` shows "Fast mode has been disabled by your organization."
135> * **Fast mode turned off by managed settings**: if your organization deploys [managed settings](/docs/en/managed-settings) that set [`fastMode: false`](/docs/en/settings-reference#fastmode), turning fast mode on with `/fast` shows the same "Fast mode has been disabled by your organization" message.
135> * **Fast mode turned off by managed settings**: if your organization deploys [managed settings](/docs/en/managed-settings.md) that set [`fastMode: false`](/docs/en/settings-reference#fastmode), turning fast mode on with `/fast` shows the same "Fast mode has been disabled by your organization" message.
136136> * **Per-session opt-in required**: managed settings that set [`fastModePerSessionOptIn: true`](#require-per-session-opt-in) refuse `/fast on` with the same message everywhere except an interactive terminal session.
137137> * **Fast-mode model not allowed**: if your organization's [`availableModels`](/docs/en/model-config#restrict-model-selection) allowlist excludes the fast-mode Opus model, turning it on is refused with "is not in your organization's allowed models". In a session already running on an allowed Opus model that supports fast mode, `/fast` instead enables fast mode on your current model without switching models.
138138
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145145 Without provisioned access, the API rejects each fast mode request with a 429, and Claude Code treats each rejection as a [fast mode rate limit](#handle-rate-limits). Unlike a rate limit's cooldown, the rejections continue until access is provisioned.
146146* **Claude AI** (Team and Enterprise): an Owner enables it at [**Organization settings > Claude Code**](https://claude.ai/admin-settings/claude-code)
147147
148Another option to disable fast mode entirely is to set `CLAUDE_CODE_DISABLE_FAST_MODE=1`. See [Environment variables](/docs/en/env-vars).
148Another option to disable fast mode entirely is to set `CLAUDE_CODE_DISABLE_FAST_MODE=1`. See [Environment variables](/docs/en/env-vars.md).
149149
150150### Use fast mode behind proxies and LLM gateways
151151
152Before offering fast mode, Claude Code checks your organization's fast mode availability with a request directly to `api.anthropic.com`. The check doesn't follow [`ANTHROPIC_BASE_URL`](/docs/en/llm-gateway-connect#set-the-base-url-and-credential), so on a network that routes Claude traffic through an [LLM gateway](/docs/en/llm-gateway) and blocks direct egress to `api.anthropic.com`, the check fails even though inference requests work. The check does use a configured [HTTP proxy](/docs/en/network-config#proxy-configuration), so a network block fails the check only where `api.anthropic.com` is unreachable even through the proxy.
152Before offering fast mode, Claude Code checks your organization's fast mode availability with a request directly to `api.anthropic.com`. The check doesn't follow [`ANTHROPIC_BASE_URL`](/docs/en/llm-gateway-connect#set-the-base-url-and-credential), so on a network that routes Claude traffic through an [LLM gateway](/docs/en/llm-gateway) and blocks direct egress to `api.anthropic.com`, the check fails even though inference requests work. The check does use a configured [HTTP proxy](/docs/en/network-config.md#proxy-configuration), so a network block fails the check only where `api.anthropic.com` is unreachable even through the proxy.
153153
154154When the check fails, `/fast` reports "Fast mode unavailable due to network connectivity issues", and requests run at standard speed, even when your organization has fast mode enabled. A check that succeeded in the past keeps working from its cached result, so a blocked check mostly affects new installations.
155155
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173173
174174### Require per-session opt-in
175175
176By default, fast mode a user turns on in an interactive session persists across sessions. To change this, set `fastModePerSessionOptIn` to `true` in any [settings file](/docs/en/settings#where-settings-live), which causes each session to start with fast mode off and requires users to explicitly enable it with `/fast`. Owners on [Team](https://claude.com/pricing?utm_source=claude_code\&utm_medium=docs\&utm_content=fast_mode_teams#team-&-enterprise) or [Enterprise](https://anthropic.com/contact-sales?utm_source=claude_code\&utm_medium=docs\&utm_content=fast_mode_enterprise) plans can deploy it organization-wide through [server-managed settings](/docs/en/server-managed-settings).
176By default, fast mode a user turns on in an interactive session persists across sessions. To change this, set `fastModePerSessionOptIn` to `true` in any [settings file](/docs/en/settings.md#where-settings-live), which causes each session to start with fast mode off and requires users to explicitly enable it with `/fast`. Owners on [Team](https://claude.com/pricing?utm_source=claude_code\&utm_medium=docs\&utm_content=fast_mode_teams#team-&-enterprise) or [Enterprise](https://anthropic.com/contact-sales?utm_source=claude_code\&utm_medium=docs\&utm_content=fast_mode_enterprise) plans can deploy it organization-wide through [server-managed settings](/docs/en/server-managed-settings.md).
177177
178178```json theme={null}
179179{
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183183
184184This is useful for controlling costs in organizations where users run multiple concurrent sessions. The user's fast mode preference is still saved, so removing this setting restores the default persistent behavior.
185185
186When managed settings set the key, `/fast on` works only in an interactive terminal session. Everywhere else, including [non-interactive mode](/docs/en/headless), the [VS Code extension](/docs/en/vs-code), and [cloud sessions](#use-fast-mode-in-cloud-sessions), it's refused with a message that your organization has disabled fast mode.
186When managed settings set the key, `/fast on` works only in an interactive terminal session. Everywhere else, including [non-interactive mode](/docs/en/headless.md), the [VS Code extension](/docs/en/vs-code.md), and [cloud sessions](#use-fast-mode-in-cloud-sessions), it's refused with a message that your organization has disabled fast mode.
187187
188188## Handle rate limits
189189
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199199If you run out of usage credits mid-session, Claude Code retries each rejected fast mode request at standard speed and pricing, so you keep working, and there is no cooldown. How you see the rejection depends on the session type:
200200
201201* In an interactive session, Claude Code shows a "Fast mode disabled · usage credits exhausted" notification and turns fast mode off for the rest of the session. Your saved fast mode preference doesn't change; run `/fast` to turn fast mode back on.
202* In [non-interactive mode](/docs/en/headless) with `--output-format stream-json`, and through the Agent SDK, Claude Code emits the same text on the message stream as a `system` message with subtype `notification`, once per turn while you're out of usage credits. Fast mode stays on. Requires Claude Code v2.1.221 or later.
202* In [non-interactive mode](/docs/en/headless.md) with `--output-format stream-json`, and through the Agent SDK, Claude Code emits the same text on the message stream as a `system` message with subtype `notification`, once per turn while you're out of usage credits. Fast mode stays on. Requires Claude Code v2.1.221 or later.
203203
204204## Research preview
205205
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213213
214214## See also
215215
216* [Model configuration](/docs/en/model-config): switch models and adjust effort levels
217* [Manage costs effectively](/docs/en/costs): track token usage and reduce costs
218* [Status line configuration](/docs/en/statusline): display model and context information
216* [Model configuration](/docs/en/model-config.md): switch models and adjust effort levels
217* [Manage costs effectively](/docs/en/costs.md): track token usage and reduce costs
218* [Status line configuration](/docs/en/statusline.md): display model and context information
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