# NousResearch/hermes-agent · MCP streamable HTTP 401 auth recovery bypass

## Open now

- 1 issue, 2 PRs open on GitHub.
- #121285: MCP streamable HTTP: a 401 on tools/call reaches the model as 'MCPError: Server returned an error response'; auth recovery never runs (mcp 2.x)
- PR #121303: fix(mcp): recover opaque Streamable HTTP tool-call 401s
- PR #125991: fix(tools): route a folded tools/call 401 through MCP auth recovery

A bug where 401 responses on tools/call requests in MCP streamable HTTP mode are surfaced as generic errors rather than triggering auth recovery, plus two fixes addressing how these 401s are routed through the recovery flow.

## TL;DR

- 3 member(s): 1 open issue(s), 0 closed issue(s), 2 open PR(s), 0 merged PR(s), 0 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evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.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 `0.67`: 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.

## Open related issues

- #121285: MCP streamable HTTP: a 401 on tools/call reaches the model as 'MCPError: Server returned an error response'; auth recovery never runs (mcp 2.x)

## Prior & competing PRs

- **#121303: fix(mcp): recover opaque Streamable HTTP tool-call 401s**. open
  - maintainer direction: category `stale_abandoned`; implication `active`; refs `a510d6c64a61582688133b5f54c8191e190a1f49`
  - files: `tests/tools/test_mcp_sse_fallback.py`, `tests/tools/test_mcp_tool_401_handling.py`, `tools/mcp_tool_errors.py`, `tools/mcp_tool_handlers.py`
- **#125991: fix(tools): route a folded tools/call 401 through MCP auth recovery**. open
  - maintainer direction: category `uncategorized`; implication `needs_llm`; refs `861f94dc4326b9de45fff009202b48415aadb9bc`, `98bf85621db123f0b3a85403d6af734013ec137d`, `b7e052c9034a08fb3211ec59b173b4507d236d4c`, `8fdbd20689d2ca8c2b5475121795d4a1c3ff3593`, `6bc0b0b07187d8d326c874ee6c8a3338f87ec6b4`
  - files: `tests/e2e/core/mcp_plugins/test_mcp_streamable_http.py`, `tests/tools/test_mcp_tool_errors.py`, `tools/mcp_tool_errors.py`, `tools/mcp_tool_handlers.py`

## Fix status

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