# NousResearch/hermes-agent · MCP boolean JSON Schema property causes full server failure

## Open now

- 1 issue, 2 PRs open on GitHub.
- #101669: MCP: boolean property schema (\`properties.x: true\`) fails ListToolsResult validation and disables the entire server
- PR #101804: fix(mcp): isolate a tool the SDK rejects instead of parking the whole server
- PR #102900: fix(mcp): accept boolean JSON Schema property schemas on tools/list

A bug where boolean property schemas (e.g. \`properties.x: true\`) in MCP tool definitions fail ListToolsResult validation and disable the entire server. The related fixes address isolating rejected tools and accepting boolean JSON Schema property schemas.

## TL;DR

- 4 member(s): 1 open issue(s), 0 closed issue(s), 2 open PR(s), 0 merged PR(s), 1 PR(s) closed without merging.
- No fix has been merged to main; one or more PRs were attempted (see below).
- **Recommended:** review the prior/competing PR(s) below. A fix was attempted but not merged; your case may extend or revive that work.

## Maintainer resolution verdict

- Internal-tracker verdict over this cluster's issue members: `unresolved`. 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evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.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.

## Open related issues

- #101669: MCP: boolean property schema (\`properties.x: true\`) fails ListToolsResult validation and disables the entire server

## Prior & competing PRs

- **#101804: fix(mcp): isolate a tool the SDK rejects instead of parking the whole server**. open
  - maintainer direction: category `implemented_elsewhere`; implication `superseded`; refs `3f1c4326760bc296a5a0c8fb6aa0d90bbc5b21fb`, `77adb80d52c70e7ff8186276d977c0fdca320311`, `48c0c3a873bc5adaf20c632b5b7630a4fac000b4`, `#101810`, `#78642`, `#98762`, `#98762`, `#98762`
  - files: `contributors/emails/[redacted:email]`, `tests/tools/test_mcp_listing_guard.py`, `tests/tools/test_mcp_streamable_http_arity.py`, `tools/mcp_listing_guard.py`, `tools/mcp_tool.py`, `tools/mcp_tool_discovery.py`, `tools/mcp_tool_health.py`, `tools/mcp_tool_transport.py`
- **#101810: fix(mcp): accept boolean JSON Schema property schemas on tools/list**. closed without merge
  - maintainer direction: category `uncategorized`; implication `needs_llm`; refs `#102117`, `#102117`
- **#102900: fix(mcp): accept boolean JSON Schema property schemas on tools/list**. open
  - maintainer direction: category `implemented_elsewhere`; implication `superseded`; refs `#101810`, `#102117`, `#101810`, `#101669`, `#102117`
  - files: `tests/tools/test_mcp_boolean_property_schema.py`, `tools/mcp_tool.py`, `tools/mcp_tool_schema.py`

## Fix status

- No merged fix on record.
- Subsystem: `mcp`