# NousResearch/hermes-agent · Tool schema rewriting causes spurious re-prefill between turns

## Open now

- Nothing open on GitHub.

A bug where tool schemas are rewritten or altered between conversation turns triggers unnecessary re-prefilling. The fixes aim to keep already-sent tool schemas byte-identical during prefix preservation and refresh cycles.

## TL;DR

- 4 member(s): 0 open issue(s), 1 closed issue(s), 0 open PR(s), 1 merged PR(s), 2 PR(s) closed without merging.
- A fix was merged to main in PR #139851. Verify it addresses your case.
- **Recommended:** read PR #139851 (and any competing PRs below) before filing. Confirm the merged change covers your symptom.

## Maintainer resolution verdict

- Internal-tracker verdict over this cluster's issue members: `resolved` · deciding PR(s): `pr-139851`. This is distinct from the fix status above. Weigh it yourself.

## How this cluster was grouped

- Link evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.
- Pairwise link density `0.50`: the share of member pairs that carry a link, counting a structural link in full and a relevance-only link at 0.36. `1.00` means every pair is linked.

## Closed / duplicate issues

- #128817: \[Bug\]: Follow-up turns re-prefill because tool schemas change between turns

## Prior & competing PRs

- **#139851: fix(tools): between-turn MCP refresh keeps sent tool schemas byte-identical (#128817, salvage #128819)**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`
  - files: `tests/tools/test_refresh_agent_mcp_tools.py`, `tools/mcp_tool_agent.py`
- **#128819: fix(tools): stop between-turn refresh from rewriting sent tool schemas**. closed without merge
  - maintainer direction: category `partial_fix`; implication `needs_llm`; refs `5675fc96bf4f8c8674a7eeb2c5736199bdca9a24`, `8d30c4eaabd85edb77a02fef6c5388d9344ef80c`, `57a22675ef9f7761111feba9d24e5c366db3134b`, `c1899de289a04d12100db370d81485cdf75e47ca`, `08f657561e0b18823d801fe80e786ff625f108b3`, `12b3e7e9a6b5d8b98d3d7da2a5ab176f0cedb4df`, `#128817`, `#129033`, `#172554`
- **#132294: fix(tools): keep already-sent tool schemas byte-identical on preserve_prefix refresh (fixes #128817)**. closed without merge
  - maintainer direction: category `implemented_elsewhere`; implication `superseded`; refs `1b11d2e70d0344b00c82219bef335f37b00573ff`, `7533bd2756b9526b52f527f737420a19e57331d7`, `f5a9361dcc66b0b972fd488b83129561509b3486`, `e94fc4e26a2a8d3967eef3bc5f5027ce418f222a`, `5675fc96bf4f8c8674a7eeb2c5736199bdca9a24`, `08f657561e0b18823d801fe80e786ff625f108b3`, `6f0ce583e0649d397752a2485108dd9628f9892c`, `6963db592ce63959d7d8bd26d458a65b03cf3940`, `164d5c2009d8b1d6d70b326739794da3f7120132`, `2a7039b0e8b53f69b1febeed60343e158db1c274`, `c1899de289a04d12100db370d81485cdf75e47ca`, `#128817`, `#128819`, `#129033`, `#172554`

## Fix status

- Merged to main in PR #139851 (cited above). No release data is tracked. Verify downstream.
- Fix last verified (merged) `2026-10-16`.
- Subsystem: `agent`