# NousResearch/hermes-agent · MCP schema repair corrupts conditional constraint branches

## Open now

- 0 issues, 1 PR open on GitHub.
- PR #104548: fix(mcp): preserve schema maps and independent required constraints

A bug causes the MCP schema sanitization process to incorrectly prune or overwrite required fields and type annotations inside oneOf, not, if/then/else, and similar conditional schema branches. Multiple fixes address preserving these constraint fragments through schema repair.

## TL;DR

- 4 member(s): 0 open issue(s), 1 closed issue(s), 1 open PR(s), 1 merged PR(s), 1 PR(s) closed without merging.
- A fix was merged to main in PR #118463. Verify it addresses your case.
- **Recommended:** read PR #118463 (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-118463`. 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evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.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

- #107141: \[Bug\]: MCP schema sanitize chain prunes required inside oneOf/not/if branches, turning mutex constraints always-false (all calls rejected)

## Prior & competing PRs

- **#118463: fix(mcp): if/then/else and oneOf constraint fragments survive schema repair (#107141, salvage #117872 #107146)**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`
  - files: `agent/moonshot_schema.py`, `contributors/emails/robchristiansen13@users.noreply.github.com`, `tests/agent/test_moonshot_schema.py`, `tests/tools/test_schema_sanitizer.py`, `tools/mcp_tool_schema.py`
- **#104548: fix(mcp): preserve schema maps and independent required constraints**. open
  - maintainer direction: category `uncategorized`; implication `needs_llm`; refs `e7c5141f1c5b`, `#118463`, `#107141`, `#117872`, `#107146`, `#4651`, `#84056`, `#55078`, `#55082`, `#56620`
  - files: `tests/tools/test_mcp_schema_property_maps.py`, `tests/tools/test_schema_sanitizer.py`, `tools/mcp_tool_schema.py`, `tools/schema_sanitizer.py`
- **#107146: fix(moonshot): stop stamping a synthetic type on if/then/else nodes**. closed without merge
  - maintainer direction: category `merged_via`; implication `superseded`; refs `e7c5141f1c5b`, `dc0915ce354d`, `#118463`, `#117872`

## Fix status

- Merged to main in PR #118463 (cited above). No release data is tracked. Verify downstream.
- Fix last verified (merged) `2026-09-21`.
- Subsystem: `mcp`