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HomeDocsClaude Code CLI 19 Oct 2026
One change · claude-code

Hooks reference changedhooks

Nearest release: v2.1.304, published under an hour before upstream edited the page. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.

Upstream edited this page at 19 Oct 2026 19:52 UTC, give or take a minute or two: the time comes from Anthropic’s own sitemap rather than from a commit. This site recorded the change at 19 Oct 2026 20:07 UTC.

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19051905| Field | Type | Example | Description |
19061906| :- | :- | :- | :- |
1907| `status` | string | `"completed"` | `"completed"` for foreground subagents, `"async_launched"` for background subagents. Subagents run in the background by default, so an Agent call that omits `run_in_background` also produces `"async_launched"` |
1907| `status` | string | `"completed"` | `"completed"` for foreground subagents, `"async_launched"` for background subagents. For which subagents run each way, see [Run subagents in foreground or background](/docs/en/sub-agents#run-subagents-in-foreground-or-background) |
19081908| `agentId` | string | `"a4d2c8f1e0b3a297"` | Identifier for the subagent run |
19091909| `content` | array | `[{"type": "text", "text": "Found 12 endpoints..."}]` | The subagent's final text blocks, or, for a subagent whose report goes through `SubagentHandback`, a short note about that hand-back in their place |
19101910| `resolvedModel` | string | `"claude-sonnet-4-5"` | Model the subagent started on, which may differ from the requested model |
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34163416| `source` | string | Where the request came from: `"command"` for `/model <name>`, the Model setting in `/config`, or turning on fast mode; `"picker"` for a model picker; `"sdk"` for a `set_model` request, or a model change in an `apply_flag_settings` request, from an Agent SDK host or Remote Control |
34173417| `context_tokens` | number | Tokens the next request re-sends as its prompt: the input, cache read, cache creation, and output tokens of the last response in the main conversation, combined. `0` before the first response |
34183418| `prompt_cache_warm` | boolean | Whether the current model's prompt cache is likely still warm, meaning the switch forfeits it |
3419| `cache_ttl` | string | [Prompt cache lifetime](/docs/en/prompt-caching#cache-lifetime) Claude Code requests for this session: `"5m"` or `"1h"` |
3419| `cache_ttl` | string | [Prompt cache lifetime](/docs/en/prompt-caching#cache-lifetime) of the main conversation at the time of this switch: `"5m"` or `"1h"` |
34203420| `estimated_cache_write_usd` | number | Estimated cost in US dollars of writing `context_tokens` to the prompt cache on `to_model` at the `cache_ttl` rate, excluding the next response. The server may not need to re-cache the whole context, so treat it as an estimate |
34213421| `pricing` | string | How Claude Code priced `estimated_cache_write_usd`: `"configured"` at your organization's own rates when it has configured them, `"catalog"` at list price, or `"default"` when `to_model` has no known price and Claude Code assumed a default rate |
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40144014Set `type` to `"agent"` and provide a `prompt` string, using `$ARGUMENTS` as a placeholder for the hook input JSON. The configuration fields are the same as [prompt hooks](#prompt-hook-configuration), except that agent hooks have a longer default timeout of 60 seconds and no `continueOnBlock` field.
40154015 
4016The response schema is `{ "ok": true }` to allow or `{ "ok": false, "reason": "..." }` to block. On `ok: false`, Claude Code handles an agent hook the way it handles a [prompt hook with `continueOnBlock: true`](#response-schema) on the same event; agent hooks have no `continueOnBlock` field, and don't support the p
4016The response schema is `{ "ok": true }` to allow or `{ "ok": false, "reason": "..." }` to block. On `ok: false`, Claude Code handles an agent hook the way it handles a [prompt hook with `continueOnBlock: true`](#response-schema) on the same event; agent hooks have no `continueOnBlo
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