Module tool_call_dedup 

Collapse redundant identical tool calls.

When an agent re-issues the same tool call with the same arguments (e.g. read_file { path: "src/lib.rs" } called at step 3 and again at step 17), the call itself is wasted tokens — the earlier response is already in history (and by this point usually already deduplicated by super::dedup).

This pass walks the buffer, hashes each ContentPart::ToolCall by (name, arguments), and replaces the arguments of later duplicates with a short [REPEAT of call_X] marker. The tool’s result block for the repeat is left untouched so the model still sees a consistent call→result pairing; dedup will have collapsed the result body if the output was identical.

Safety

• Only the arguments string is rewritten. Name, id, and thought_signature are preserved so every provider adapter still round-trips.
• Tool calls in the most recent KEEP_LAST_MESSAGES messages are never touched — the model is likely actively reasoning over them.
• Only triggers when arguments exceed MIN_COLLAPSE_BYTES so micro-arguments like {} stay readable.

Rollout

This strategy is intentionally kept out of the default-safe super::apply_all path because replacing historical arguments with back-references can erase still-relevant call details.

Constants

KEEP_LAST_MESSAGES

Keep tool-call arguments verbatim in this many trailing messages.

MIN_COLLAPSE_BYTES

Tool-call arguments shorter than this are never collapsed.

Functions

collapse_duplicate_calls

Collapse duplicate tool-call arguments into short back-references.