overview changedagents-and-tools/tool-use/overview
Nearest release: v2.1.281, published an hour before this site recorded the change. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.
Recorded here
Lines+20added
Lines−16removed
From line
864
where the diff opens
First seen
14 Aug 2026
this site's first read of the page
Recorded edits9to this page, all time
The whole hunk
from line 864, old and new numbered
/
from line 864
864864
865865When you use `tools`, the API also automatically includes a special system prompt for the model that enables tool use. The number of tool use tokens required for each model is listed in the following table (excluding the additional tokens listed earlier). Note that the table assumes at least 1 tool is provided. If no `tools` are provided, then a tool choice of `none` uses 0 additional system prompt tokens.
866866
867| Model | Tool choice | Tool use system prompt token count |
868| ------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------ | ---------------------------------- |
869| Claude Opus 5.5 | `auto`, `none` | 286 tokens |
870| Claude Opus 5 | `auto`, `none`***`any`, `tool` | 286 tokens***406 tokens |
871| Claude Opus 4.8 | `auto`, `none`***`any`, `tool` | 290 tokens***410 tokens |
872| Claude Opus 4.7 | `auto`, `none`***`any`, `tool` | 675 tokens***804 tokens |
873| Claude Opus 4.6 | `auto`, `none`***`any`, `tool` | 497 tokens***589 tokens |
874| Claude Opus 4.5 | `auto`, `none`***`any`, `tool` | 496 tokens***588 tokens |
875| Claude Opus 4.1 ([retired, except on Bedrock and Google Cloud](https://platform.claude.com/docs/en/about-claude/model-deprecations)) | `auto`, `none`***`any`, `tool` | 313 tokens***315 tokens |
876| Claude Opus 4 ([retired, except on Google Cloud](https://platform.claude.com/docs/en/about-claude/model-deprecations)) | `auto`, `none`***`any`, `tool` | 313 tokens***315 tokens |
877| Claude Sonnet 5 | `auto`, `none`***`any`, `tool` | 354 tokens***474 tokens |
878| Claude Sonnet 4.6 | `auto`, `none`***`any`, `tool` | 497 tokens***589 tokens |
879| Claude Sonnet 4.5 | `auto`, `none`***`any`, `tool` | 496 tokens***588 tokens |
880| Claude Sonnet 4 ([retired, except on Bedrock and Google Cloud](https://platform.claude.com/docs/en/about-claude/model-deprecations)) | `auto`, `none`***`any`, `tool` | 313 tokens***315 tokens |
881| Claude Haiku 4.5 | `auto`, `none`***`any`, `tool` | 496 tokens***588 tokens |
882| Claude Haiku 3.5 ([retired, except on Bedrock and Google Cloud](https://platform.claude.com/docs/en/about-claude/model-deprecations)) | `auto`, `none`***`any`, `tool` | 264 tokens***355 tokens |
867| Model | Tool use system prompt tokens: auto, none | Tool use system prompt tokens: any, tool |
868| :------------------------------------------------------------------------------------------------------------------------------------ | :---------------------------------------- | :--------------------------------------- |
869| Claude Opus 5.5 | 286 tokens | |
870| Claude Opus 5 | 286 tokens | 406 tokens |
871| Claude Opus 4.8 | 290 tokens | 410 tokens |
872| Claude Opus 4.7 | 675 tokens | 804 tokens |
873| Claude Opus 4.6 | 497 tokens | 589 tokens |
874| Claude Opus 4.5 | 496 tokens | 588 tokens |
875| Claude Opus 4.1 ([retired, except on Bedrock and Google Cloud](https://platform.claude.com/docs/en/about-claude/model-deprecations)) | 313 tokens | 315 tokens |
876| Claude Opus 4 ([retired, except on Google Cloud](https://platform.claude.com/docs/en/about-claude/model-deprecations)) | 313 tokens | 315 tokens |
877| Claude Sonnet 5 | 354 tokens | 474 tokens |
878| Claude Sonnet 4.6 | 497 tokens | 589 tokens |
879| Claude Sonnet 4.5 | 496 tokens | 588 tokens |
880| Claude Sonnet 4 ([retired, except on Bedrock and Google Cloud](https://platform.claude.com/docs/en/about-claude/model-deprecations)) | 313 tokens | 315 tokens |
881| Claude Haiku 4.5 | 496 tokens | 588 tokens |
882| Claude Haiku 3.5 ([retired, except on Bedrock and Google Cloud](https://platform.claude.com/docs/en/about-claude/model-deprecations)) | 264 tokens | 355 tokens |
883
884* **auto, none:** The count when tool\_choice is auto or none.
885* **any, tool:** The count when tool\_choice is any or tool.
886* **Retired:** May still be available on other cloud platforms. See [Model deprecations](https://platform.claude.com/docs/en/about-claude/model-deprecations) for more.
883887
884888These token counts are added to your normal input and output tokens to calculate the total cost of a request.
885889
No line in this hunk matches that.