# NousResearch/hermes-agent · MCP protocol version header handling fixes

## Open now

- Nothing open on GitHub.

Multiple issues and fixes related to the incorrect injection of the \`mcp-protocol-version\` header on the MCP \`initialize\` request, which violates the MCP spec and causes initialization failures with certain servers. Fixes also address SSE transport fallback behavior.

## TL;DR

- 3 member(s): 0 open issue(s), 1 closed issue(s), 0 open PR(s), 1 merged PR(s), 1 PR(s) closed without merging.
- A fix was merged to main in PR #106432. Verify it addresses your case.
- **Recommended:** read PR #106432 (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-106432`. 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evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.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 `0.67`: 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

- #53676: \[Bug\]: MCP HTTP transport: wigai server fails to initialize, ends as 0 active MCP servers

## Prior & competing PRs

- **#106432: fix(mcp): SSE-only MCP servers now connect via automatic transport fallback (salvage #53764)**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`
  - files: `tests/tools/test_mcp_sse_fallback.py`, `tools/mcp_tool.py`, `tools/mcp_tool_errors.py`, `tools/mcp_tool_transport.py`
- **#53764: fix(mcp): auto-fallback to SSE transport when Streamable HTTP returns…400**. closed without merge
  - maintainer direction: category `merged_via`; implication `superseded`; refs `a565e2d49350`, `#106432`

## Fix status

- Merged to main in PR #106432 (cited above). No release data is tracked. Verify downstream.
- Fix last verified (merged) `2026-09-13`.
- Subsystem: `mcp`