fine-grained-tool-streaming changedagents-and-tools/tool-use/fine-grained-tool-streaming
Nearest release: v2.1.309, 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+1added
Lines−1removed
From line
16
where the diff opens
First seen
14 Aug 2026
this site's first read of the page
Recorded edits13to this page, all time
The whole hunk
from line 16, old and new numbered
/
from line 16
1616
1717## How to use fine-grained tool streaming
1818
19All models support fine-grained tool streaming on the Claude API, [Amazon Bedrock](https://platform.claude.com/docs/en/build-with-claude/claude-in-amazon-bedrock), [Claude Platform on AWS](https://platform.claude.com/docs/en/build-with-claude/claude-platform-on-aws), [Google Cloud](https://platform.claude.com/docs/en/build-with-claude/claude-on-vertex-ai), and [Microsoft Foundry](https://platform.claude.com/docs/en/build-with-claude/claude-in-microsoft-foundry). To use it, set `eager_input_streaming` to `true` on any user-defined tool where you want fine-grained streaming enabled, and enable streaming on your request.
19All models support fine-grained tool streaming on the Claude API, [Amazon Bedrock](https://platform.claude.com/docs/en/build-with-claude/claude-in-amazon-bedrock), [Claude Platform on AWS](https://platform.claude.com/docs/en/build-with-claude/claude-platform-on-aws), [Claude Models on Google Cloud (Google managed)](https://platform.claude.com/docs/en/build-with-claude/claude-models-on-google-cloud/google-managed), and [Microsoft Foundry](https://platform.claude.com/docs/en/build-with-claude/claude-in-microsoft-foundry). To use it, set `eager_input_streaming` to `true` on any user-defined tool where you want fine-grained streaming enabled, and enable streaming on your request.
2020
2121The `eager_input_streaming` field is optional. Setting it to `true` turns on fine-grained streaming for that tool, and omitting it gives you standard buffered streaming, in which the API buffers and validates each parameter value before streaming it back. The exception is a request that still sends the legacy `fine-grained-tool-streaming-2025-05-14` beta header, which turns fine-grained streaming on for tools that leave the field unset. The per-tool field replaces that header, and an explicit `false` keeps buffered streaming for a tool even when a request still sends it. The legacy header cannot be combined with a [computer use](https://platform.claude.com/docs/en/agents-and-tools/tool-use/computer-use-tool) or [browser use](https://platform.claude.com/docs/en/agents-and-tools/tool-use/browser-use-tool) toolset entry: the API rejects a request that sends both, so remove the header and set `eager_input_streaming` on the user-defined tools that need it. See [Tool reference](https://platform.claude.com/docs/en/agents-and-tools/tool-use/tool-reference) for the field definition.
2222
No line in this hunk matches that.