Source Intelligence

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

All of v2.1.63 Home All releases olderv2.1.62 v2.1.64newer
Claude Code v2.1.63

Tool Result Summarization [Gradual Rollout]

What

A feature that instructs the model to preserve important information from tool results in its response text, since original tool results may be cleared later (for context window management).

Status

Feature-flagged via tengu_summarize_tool_results (default false)

Details
  • When enabled, appends a system instruction: "When working with tool results, write down any important information you might need later in your response, as the original tool result may be cleared later."
  • Prepares for a future where tool results are more aggressively pruned from context
Evidence

Gated by tengu_summarize_tool_results flag (search for "tengu_summarize_tool_results")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.63 →