When an MCP stdio subprocess fails to connect (token expiry, port
contention, timeout), the run() reconnect loop retries with backoff.
Each retry calls _run_stdio() which spawns a new process pair, but the
previous failed pair was only detected as orphaned (added to
_orphan_stdio_pids) — never actually killed. This caused rapid zombie
accumulation: 5 failed attempts × 2 procs each = 10 orphans competing
for the same port.
Add a _kill_orphaned_mcp_children() call at the top of _run_stdio(),
before the _snapshot_child_pids() baseline, so any orphans from prior
failed attempts are reaped before a new subprocess is spawned.
Fixes#57355
register_mcp_servers now nudges cached entries whose session is None
via _signal_reconnect, so a new agent session recovers a parked server
immediately instead of waiting up to _PARKED_RETRY_INTERVAL for the
next self-probe (#50170). Gate-check idea credit: @izumi0uu (#50184),
@LeonSGP43 (#37772), @Tranquil-Flow (#37899).
_wait_for_server_session_ready used a time.monotonic deadline; the
circuit-breaker tests freeze monotonic, turning the loop into an
infinite spin (300s SIGKILL in CI-parity runs). Bound by iteration
count instead.
Some MCP servers (e.g. Spring Boot apps with a React SPA) serve their
frontend on any unmatched GET route. The MCP endpoint works perfectly
via POST (JSON-RPC), but a GET to /mcp falls through to the SPA
controller and returns text/html. Hermes's preflight content-type probe
sees HTML instead of application/json or text/event-stream and refuses
to connect.
This adds a per-server config option that
bypasses the content-type probe, letting the SDK connect directly via
POST where it works fine.
```yaml
mcp_servers:
stirling-pdf:
url: http://localhost:8090/mcp
headers:
X-API-KEY: <key>
skip_preflight: true
```
Related: #52460 (OAuth redirect preflight), #51600 (skip probe on mcp add),
#40366 (skip probe on reconnect — already merged).
Some MCP servers (e.g. DocuSeal) serve their web UI on HEAD/GET but
speak Streamable HTTP only via POST. The preflight probe now tries a
lightweight JSON-RPC `initialize` POST before rejecting endpoints
whose HEAD/GET returns a non-MCP content type (e.g. `text/html`).
If the POST returns `application/json` or `text/event-stream` with a
2xx status, the endpoint is accepted. Otherwise the original rejection
behaviour is preserved.
Adds 5 new test cases covering the POST probe path:
- POST rescues HTML HEAD with JSON response
- POST rescues HTML HEAD with event-stream response
- POST still rejects when it also returns HTML
- POST still rejects on non-2xx status
- POST not attempted when HEAD already returns valid MCP content type
Parking deregisters the server's tools, which removes the only paths
that could ever set _reconnect_event (circuit-breaker half-open probe
and _signal_reconnect both live inside registered tool handlers). A
parked server was therefore unrevivable short of a manual /mcp reload —
the park comment's promised breaker wake could never fire.
Make the parked wait a timed wait: every _PARKED_RETRY_INTERVAL (300s)
the run task wakes and attempts one revival probe, re-parking on
failure instead of burning the full 5-retry budget each cycle. Explicit
reconnect requests still wake it immediately. Idea credit: @Hellbayne
(PR #38881, earliest never-abandon proposal), reconciled with the
park design from #53599.
_discover_tools only filled self._tools; registry registration happened
only in _discover_and_register_server (initial start) and _refresh_tools.
After parking deregistered a server's tools, a revival rebuilt the
transport but published zero tools — a phantom recovery.
Register freshly discovered tools whenever _ready is set and the
registry entry list is empty. Extracted from PR #54139 by @nicha16
(the remainder of that PR reverses the park design and is not taken).
The local retries variable in MCPServerTask.run() accumulated across
transient disconnections — each transport exception incremented it, but
only clean transport returns (auth recovery / manual refresh) or
park-wake reset it. Five transient blips over a long-uptime gateway
would permanently park the MCP server.
Promote retries to instance attribute _reconnect_retries and reset it
at all 4 session-establishment sites in _run_stdio / _run_http, so only
consecutive failures without successful reconnection count toward the
parking budget.
Fixes#57604
Port from anomalyco/opencode#33533. Native MCP tools now register as
mcp__<server>__<tool> (double-underscore delimiter) instead of
mcp_<server>_<tool>, aligning with the convention used by Claude Code,
Codex, and OpenCode.
The double-underscore delimiter disambiguates the server/tool boundary
even when either component contains underscores (the single-underscore
form was ambiguous, which is why is_mcp_tool_parallel_safe already had to
track provenance in a side-map). It also unifies native registration with
the Anthropic-OAuth wire form (_MCP_TOOL_PREFIX = 'mcp__'), so the
single->double promotion that path performed is now a no-op for native
tools while still handling legacy replayed names.
- tools/mcp_tool.py: add MCP_TOOL_NAME_PREFIX + mcp_prefixed_tool_name()
helper; route _convert_mcp_schema, utility schemas, refresh stale-set,
and the parallel-safe prefix gate through it
- agent/transports/codex_event_projector.py: mirror convention in the
deterministic call_id input for MCP server-executed tool calls
- tests: update produced-name assertions to the new convention
Port from anomalyco/opencode#34529: MCP servers can emit
notifications/message logging notifications (RFC 5424 levels), but the
MCP SDK's default logging_callback silently discards them — server-side
warnings/errors during tool calls were invisible.
- tools/mcp_tool.py: pass a logging_callback to every ClientSession
(stdio, SSE, streamable HTTP old+new API paths via the shared
sampling_kwargs sites), mapping the 8 MCP log levels onto Python
logging levels and tagging entries with [server/logger] origin.
- JSON-serialize non-string payloads, cap at 2000 chars so a chatty
server can't flood agent.log, never raise from the handler.
- Gated on SDK support (_check_logging_callback_support) mirroring the
existing message_handler gate for old SDK versions.
- tests/tools/test_mcp_server_log_notifications.py: 10 tests covering
level mapping, origin tagging, JSON payloads, truncation, and the
never-raise contract.
A Cursor-style MCP manager inside Capabilities, plus the backend it needs.
- Server list with brand/favicon avatars + live status dot and a capability
summary (N tools, M prompts, K resources); Servers | Catalog views.
- Catalog: one-click install of Nous-approved servers with required-env prompts.
- GUI OAuth: Authenticate opens the system browser from the TTY-less backend and
verifies a token actually lands; header/API-key servers are never pushed down
OAuth; a dirty mcp.json can't drop a freshly-persisted auth field.
- Full-width mcp.json editor (ecosystem document format) + pinned stdio/agent
LogTail; probes cached 5m and keyed by (profile, config) so revisiting never
respawns the fleet or shows a stale probe.
- Whole-map persistence (PUT /api/mcp/servers) so deletes/toggles actually stick
(the generic /api/config deep-merge could not remove keys).
- perf: MCP probe/auth no longer hold the global skills lock, so a slow stdio
spawn can't stall every other request into a 15s timeout.
- per-tool include/exclude gating (lib/mcp-tool-filter) mirroring the CLI loader.
Root cause: gateway spawns LSP servers (jdtls/pyright/yaml-ls) and
slash_worker without start_new_session=True, so they inherit the
gateway process group (= TUI parent PID). When mcp_tool
_snapshot_child_pids() races with these spawns during stdio MCP
server startup, non-MCP children leak into _stdio_pgids with the
TUI parent PGID. shutdown_mcp_servers() then killpg(tui_parent_pid,
SIGTERM), killing the TUI itself.
Evidence: tui_gateway_crash.log shows recurring SIGTERM stacks:
shutdown_mcp_servers -> _kill_orphaned_mcp_children ->
_send_signal -> killpg(pgid, sig) -> SIGTERM received
Fix (3 layers):
1. agent/lsp/client.py: add start_new_session=True to LSP server
spawn so each LSP server gets its own process group/session.
2. tui_gateway/server.py: same fix for slash_worker spawn, the
symmetric root-cause patch so no gateway direct child shares
the TUI parent pgid.
3. tools/mcp_tool.py: add _filter_mcp_children() defense-in-depth
that drops non-MCP children (slash_worker, jdtls/eclipse LSP)
from the PID delta before they can poison _stdio_pgids.
The MCP input-schema normalizer in _normalize_mcp_input_schema promotes the
legacy JSON Schema 'definitions' meta-keyword to '$defs' (draft 2019-09+)
so local '$ref' resolution works downstream. The previous walk renamed
*any* key named 'definitions' anywhere in the tree, including inside
'properties' dicts. That turned user-facing parameter names into '$defs',
producing property keys that contain '$', which Anthropic and OpenAI
both reject with HTTP 400 (pattern '^[a-zA-Z0-9_.-]{1,64}$').
Real-world repro: an MCP server that exposes a CI/pipelines tool whose
'definitions' parameter is an array of pipeline-definition IDs. Such a tool
is enough on its own to break every conversation, because the full tools
array is sent on every request.
Fix: when descending into a 'properties' or 'patternProperties' mapping,
iterate property-name -> schema pairs directly, leaving the property names
verbatim. Ordinary JSON Schema semantics resume inside each property's
schema, so a legitimately nested 'definitions' meta-keyword inside a
property's schema is still promoted.
Adds two regression tests:
- test_definitions_as_property_name_is_preserved (the property-name case)
- test_definitions_property_and_meta_keyword_coexist (both forms in one
schema; the property name stays, the meta-keyword promotes)
OAuth-protected MCP servers (e.g. Hospitable) return 200 text/html on an
unauthenticated HEAD probe — a login/landing page the server cannot substitute
for a real MCP response without a Bearer token. The preflight cannot
distinguish this from a misconfigured URL, so it raises NonMcpEndpointError
before the OAuth browser flow has a chance to run.
Add `and self._auth_type != "oauth"` to the preflight condition in
MCPServerTask.run(). The probe is inapplicable to OAuth servers: their URL
legitimacy is established by .well-known/oauth-protected-resource during the
OAuth handshake, not by a GET content-type check.
Concrete repro: Hospitable (https://mcp.hospitable.com/mcp) returns
`200 text/html` to an unauthenticated httpx HEAD. Without the guard:
✗ NonMcpEndpointError at `hermes mcp test`
With the guard:
✓ Connected (1487ms) — 63 tools discovered
Relation to open PRs:
- #37598 adds a POST probe fallback for POST-only non-OAuth servers (e.g.
DocuSeal), but only passes when POST returns 2xx + MCP content-type.
Hospitable returns 401 on the POST probe (Bearer challenge), so #37598
does not cover this case.
- #49463 extends the POST probe to also pass on non-2xx auth challenges
(making it OAuth-aware), but is labeled duplicate of #37598 and may not
land independently.
This fix is complementary: it handles OAuth servers with zero extra
round-trips rather than adding a POST probe step.
Tests:
- test_oauth_server_html_response_raises_without_skip: documents that
_preflight_content_type raises NonMcpEndpointError for 200 text/html
(the underlying issue), with an OAuth-server docstring.
- test_run_skips_preflight_for_oauth: verifies that run() does NOT invoke
_preflight_content_type when auth_type=="oauth", using class-level
monkeypatching so the gate is exercised without a live MCP transport.
23 passed tests/tools/test_mcp_preflight_content_type.py
A long-running gateway session could permanently lose an MCP server: once a
stdio subprocess died (or transient drops accumulated over the session), the
run loop exhausted its reconnect budget and returned, orphaning the task. With
no listener for _reconnect_event, the circuit breaker's half-open probe could
never revive the server — every probe hit a dead/absent session, re-armed the
60s cooldown, and looped forever until a full gateway restart (#16788).
Root cause was split ownership of transport liveness between the run loop and
the tool handler, plus a permanent give-up path. Fixed by one invariant: a
non-shutdown server task is always reconnectable.
- run loop parks (deregisters phantom tools, then awaits _reconnect_event)
instead of returning when the reconnect budget is exhausted, so the task
stays alive as a dormant listener
- retry budget resets on every successful (re)connect, so a healthy
long-lived server can't accumulate lifetime drops into a death sentence
- half-open probe with no live session signals a reconnect (reviving a
parked/dead task and respawning a dead stdio subprocess) and returns a
clean 'reconnecting' error instead of writing into a dead pipe
- breaker resets on successful session init across all transports
(stdio/HTTP/SSE) — fully transport-agnostic, no PID/pipe polling
Builds on the closed-PR cluster for this issue: keeps #49255's deregister-on-
exhaustion insight and #21006's signal-don't-probe insight, discards the racy
os.kill PID machinery.
Co-authored-by: LeonSGP43 <LeonSGP43@users.noreply.github.com>
Co-authored-by: srojk34 <srojk34@users.noreply.github.com>
During stdio MCP server startup, _run_stdio (an async method) called the
synchronous check_package_for_malware() inline. That makes a blocking
urllib HTTPS POST to api.osv.dev whose own timeout doesn't reliably cover a
stalled SSL handshake, so an intermittent network issue froze the entire
asyncio event loop for up to ~120s — blowing past the TUI/gateway's 15s
startup budget and showing "gateway startup timeout".
Run the check via asyncio.to_thread (off the loop) AND bound it with
asyncio.wait_for(timeout=_OSV_MALWARE_CHECK_TIMEOUT_S=12s). The malware check
is fail-open, so on timeout we log and proceed rather than blocking startup.
Salvaged from #29190 by @qdaszx (re-applied on current main — the call site
moved since the PR was opened), combining the to_thread approach also proposed
in #29192 by @ygd58. Two load-bearing tests: event-loop-not-blocked-during-
check and timeout-fails-open — both mutation-verified to fail against the old
inline blocking call.
Closes#29184.
Co-authored-by: ygd58 <buraysandro9@gmail.com>
/reload-mcp -> shutdown_mcp_servers -> _kill_orphaned_mcp_children(include_active=True)
-> _send_signal -> killpg(pgid, SIGTERM). When a tracked MCP stdio child shares
the gateway's OWN process group, killpg delivers SIGTERM to the gateway itself,
firing its SIGTERM handler -> os._exit(0): /reload-mcp crashes the gateway.
Pre-compute the gateway's own pgid (os.getpgrp(), None on Windows/restricted)
and, in _send_signal, skip killpg when pgid == own pgid, falling through to the
per-pid os.kill path so the child is still reaped without self-signaling.
Adds a regression test (folded in) that pins the guard: with a tracked pgid
equal to the gateway's own pgid, killpg is never called for that pgid and the
per-pid kill fallback is used. Mutation-checked.
Co-authored-by: kshitijk4poor <82637225+kshitijk4poor@users.noreply.github.com>
A server that doesn't implement the optional 'ping' utility answers a
keepalive ping with JSON-RPC method-not-found. _is_method_not_found_error
latches that condition so the probe falls back to list_tools instead of
reconnect-looping.
The substring fallback only matched 'method not found' / '-32601' /
'not found: ping'. Servers that surface method-not-found as the common
'Unknown method: <name>' phrasing without a structural -32601 code (e.g.
agentmemory's MCP server) slipped through, so the fallback never latched
and the keepalive reconnect-looped every cycle.
Add 'unknown method' to the substring fallback so the ping->list_tools
keepalive fallback latches for these servers too.
Fixes#50028.
MCP Streamable HTTP servers that garbage-collect idle sessions on a short
TTL (e.g. Unreal Engine's editor MCP, ~15s) were unusable: the keepalive
was hardcoded at 180s, so the session was always dead by the time it ran,
and every idle tool call then landed on an expired session and paid the
full reconnect path (observed hangs of 113-143s until interrupt, bounded
only by the 300s tool_timeout).
Two coordinated, backward-compatible changes:
- Add per-server `keepalive_interval` (config.yaml, not an env var per the
contribution rubric). Default 180s — byte-identical to the old hardcoded
value when unset — floored at 5s. Servers with short session TTLs set it
below their TTL so the session stays warm.
- Switch the keepalive probe from `list_tools()` to `ping` (the MCP base
protocol liveness primitive). On large servers `list_tools` pulled ~1 MB
every cycle (830 tools = 1,068,041 bytes); `ping` is ~55 bytes and works
uniformly across tool/prompt/resource servers. Tool-list changes still
arrive out-of-band via notifications/tools/list_changed -> _refresh_tools.
`ping` is an OPTIONAL utility, so to guarantee zero regression for a
tool-capable server that doesn't implement it: the first -32601 latches
`_ping_unsupported` and the probe falls back to the pre-ping `list_tools`
path for that connection (no reconnect loop). The latch resets on each
fresh connection (_discover_tools, all transport paths) so a server that
gains ping support after a reconnect is re-probed with the cheap path.
Non-(-32601) ping errors propagate as genuine liveness failures.
Verified end-to-end against a live Unreal MCP server (idle 22s past the
~15s TTL -> post-idle tool call returns in 0.31s, no teardown) and with a
simulated ping-less tool server driving the real keepalive loop (ping once,
list_tools thereafter, no reconnect). 25/25 unit tests pass.
Note: a separate upstream defect (modelcontextprotocol/python-sdk#2604)
still tears down the whole session when one tool-call POST returns 4xx;
that is not addressed here.
CI caught 3 ACP test failures (tests/acp/test_server.py,
tests/acp/test_mcp_e2e.py). Root cause: routing ACP's tool-surface rebuild
through the shared refresh_agent_mcp_tools helper (added in the round-2 pass)
broke a deliberate, pre-existing ACP contract:
- the ACP tests assert `agent.tools is <get_tool_definitions return>` (object
identity) and an exact get_tool_definitions(enabled_toolsets=[...],
disabled_toolsets=..., quiet_mode=True) call signature; the shared helper
list()-copies and re-derives differently, breaking identity; and
- the tests use a MagicMock agent whose _tool_snapshot_generation is a mock, so
the new `int < published_gen` generation guard raised TypeError and the whole
ACP refresh silently failed.
ACP already preserves memory-provider tools (its own inject call) and excludes
context_engine, so there was no bug to fix there — only over-reach. Reverted ACP
to its original rebuild. (Same lesson as the gateway path: leave call sites that
carry their own tested contract alone; a reviewer's "inert today, fragile" note
meant leave-it, not change-it.)
Also hardened the generation guard defensively: tolerate a non-int
_tool_snapshot_generation (mock / partially-built agent) instead of throwing
TypeError and silently failing the refresh.
Second review pass (Codex + Hermes subagent). Codex reproduced a real race with
a two-thread harness; both converged on the remaining issues.
- Generation-aware publish (fixes a lost-update race): two refresh callers (the
late-refresh daemon and the between-turns prologue around turn 1) could each
compute a snapshot outside the lock; a SLOWER caller holding an OLDER registry
generation could acquire the publish lock after a newer caller and clobber it,
deleting just-landed tools. refresh_agent_mcp_tools now captures
registry._generation before computing and refuses to publish a stale set;
agent._tool_snapshot_generation tracks the published generation.
- Context-engine routing names (_context_engine_tool_names) are now staged on a
local and published atomically with the snapshot, and only claimed when this
rebuild actually appended the schema — matching agent_init's dedup so a
registry/plugin tool of the same name keeps its own dispatch. (Previously
mutated live, before the publish lock, and on no-change refreshes.)
- CLI /reload-mcp: self.enabled_toolsets is resolved once at startup, so a
server newly ENABLED in config mid-session wasn't picked up (TUI already
re-resolved). Merge now-connected MCP server names into the override (unless
the user pinned all/*), mirroring startup, and keep self.enabled_toolsets in
sync. Closes the CLI/TUI parity hole.
- ACP (acp_adapter/server.py) routed through the shared helper — it was a 5th
sibling rebuild that re-injected memory tools but NOT context-engine tools and
bypassed the atomic/name-diff path (inert today, fragile).
- mcp_startup._resolve_discovery_timeout pulls its default from DEFAULT_CONFIG
(single source of truth) instead of a stale hardcoded 5.0 literal.
- Tests: stale-generation-no-clobber, _skip_mcp_refresh honored, timeout
fallback uses DEFAULT_CONFIG.
Consolidated findings from three independent reviewers (Codex, Claude Code, a
Hermes subagent w/ the hermes-agent-dev skill):
- BLOCKING: refresh_agent_mcp_tools rebuilt only the registry subset, silently
dropping post-build-injected memory-provider (mem0/honcho/…) and context-
engine (lcm_*) tools on every refresh. Now additive-preserving: re-applies
the same injectors agent_init uses, staged on locals and published atomically.
- Re-injection now honors the #5544 enabled_toolsets gate for context-engine
tools, so a restricted-toolset platform can't get lcm_* leaked back in.
- Atomic read-diff-publish under one lock: the returned `added` set and the
(tools, valid_tool_names) pair are consistent even under concurrent callers
(no half-swap, no TOCTOU).
- background_review fork opts out (_skip_mcp_refresh) so its byte-identical
tools[] cache parity with the parent is preserved.
- CLI /reload-mcp routed through the shared helper (was a 4th divergent copy
with the same clobber bug + missing disabled_toolsets).
- Explicit reloads (TUI RPC + CLI) pass enabled_override so a server the user
just enabled in config this session is picked up; automatic paths reuse the
agent's build-time selection.
- mcp_discovery_timeout default 5.0 -> 1.5s: correctness now comes from the
between-turns refresh, so the startup wait is only a small turn-1 UX bump
rather than a heavy dead-server latency penalty.
- has_registered_mcp_tools checks registered TOOLS (not connected servers) so a
zero-tool/prompt-only server doesn't make the per-turn hook fire forever.
- Tests: rewrote the thread-safety test to actually exercise the write path
(alternating tool sets), added the #5544-gate regression, the memory/context
preservation regression, and a "callable next turn via valid_tool_names"
contract; removed a dead monkeypatch line.
A slow MCP server (HTTP/OAuth, 2-6s cold connect) that finishes connecting
after the agent's one-time tool snapshot was uncallable for the rest of the
session. The merged pre-first-turn late-refresh only helps during the dead air
before the user's first keystroke; once a turn starts it bails to protect the
prompt cache, so a user who types before the server connects never gets the
tools without a manual /reload-mcp.
Refresh the snapshot in the per-turn prologue (build_turn_context), before this
turn's first API call assembles tools=. This is cache-safe by construction: the
refresh only ever extends a fresh request prefix at a turn boundary, never
mutates the cached prefix of an in-flight turn. So late tools become callable on
the user's NEXT turn automatically, with no /reload-mcp and no cache cost.
- tools/mcp_tool.py: has_registered_mcp_tools() — cheap guard so sessions with
no MCP servers (the common case) skip the rebuild entirely.
- agent/turn_context.py: call the shared refresh_agent_mcp_tools() helper at the
top of the prologue when MCP servers are registered.
- tests: 3 contract tests through the real build_turn_context (adds late tool;
skipped when no servers; no snapshot churn when unchanged).
.hermes/plans/: SPEC + PLAN documenting the root cause, the cache-safety
constraint, and why the existing fixes (#48403/#41630/#42802) don't close it.
MCP servers that connect after the agent's one-time tool snapshot were
invisible for the whole session. Two root causes, fixed together:
1. The startup discovery wait was a flat 0.75s. HTTP/OAuth servers
commonly take 2-6s on a cold connect, so they missed the window and
their tools never entered the agent's snapshot. `thread.join(timeout)`
already returns the instant discovery completes, so raising the bound
costs ~0s for the common case (no MCP / fast servers) and only ever
blocks for a genuinely-pending server, capped so a dead server can't
freeze startup. The bound is now configurable via
`mcp_discovery_timeout` (config.yaml, default 5.0s).
2. Three call sites duplicated the agent tool-snapshot rebuild (the TUI
`reload.mcp` RPC, the gateway reload, and the TUI late-binding refresh
thread), and the late-refresh detected changes by tool COUNT — missing
an equal-size add/remove swap. Consolidated into one shared
`tools.mcp_tool.refresh_agent_mcp_tools(agent)` helper that diffs by
tool NAME, mutates the agent under a lock (thread-safe), and respects
the agent's own enabled/disabled toolsets.
The late-binding refresh keeps its pre-first-turn cache-safety guard:
it never rebuilds the tool list once a turn has started, so the cached
prompt prefix is never invalidated mid-conversation.
Tests: new tests/tools/test_refresh_agent_mcp_tools.py covers the
name-based diff, in-place mutation, agent-scoped filtering, thread
safety, and the config-driven discovery bound (incl. instant-return
when nothing is pending). 75 passed across the touched areas.
Wires support for the MCP `elicitation/create` request (Python SDK 1.11+)
so MCP servers can ask the user to confirm sensitive operations
mid-tool-call (payment authorization, OAuth confirmation, etc.) instead
of failing closed or requiring out-of-band biometrics.
Behavior:
- `tools/mcp_tool.py` adds `ElicitationHandler`, attached per server task
and passed to `ClientSession` as `elicitation_callback`. Form-mode
requests route through the existing approval system; URL-mode requests
decline cleanly (out of scope for this pass).
- `tools/approval.py` adds `request_elicitation_consent()`, which dispatches
to whichever surface owns the active session — `_await_gateway_decision`
for Telegram / Slack / etc. (so the approval prompt lands on the right
platform), `prompt_dangerous_approval` for CLI / TUI. Fails closed on
timeout, missing notify_cb, or exception.
- The MCP tool wrapper snapshots `contextvars.copy_context()` into
`MCPServerTask._pending_call_context` before each `session.call_tool`
and clears it after. The recv-loop task that dispatches incoming
`elicitation/create` requests does not inherit the agent task's
contextvars (HERMES_SESSION_PLATFORM and friends), so without the
bridge `_is_gateway_approval_context()` returns False on every
gateway session and the elicitation falls through to a CLI prompt
that has no TTY → fail-closed decline. The handler now reads the
snapshot via its `owner` back-reference and replays it through
`Context.copy().run(...)` so attribution survives the task hop.
Tests (`tests/tools/test_mcp_elicitation.py`):
- form-mode accept / decline / cancel
- URL-mode declined without prompting
- exception in approval system → decline
- timeout in approval → cancel
- context-bridge regression tests (replay observed in consent call,
missing-context fallback, multiple-replay safety, owner with
cleared `_pending_call_context`)
Verified end-to-end against pay's MCP server on macOS: agent message
arrives via Telegram, agent calls `mcp_pay_curl` against a paid endpoint,
pay returns 402, ElicitationHandler routes the approval prompt back to
the originating Telegram chat, user replies in TG, the curl tool signs
and completes.
Platforms tested: macOS 14 (darwin/arm64). No Unix-only syscalls
introduced; Windows footgun checker passes on the touched files.
The credential gate. When multiplexing is active, a profile's secrets resolve
from a context-local scope, never the process-global os.environ (which in a
multiplexer may hold another profile's keys, and is inherited by every
subprocess spawned with env=dict(os.environ)).
- agent/secret_scope.py: get_secret() backed by a secret-scope contextvar.
FAIL-CLOSED: when multiplex is active and no scope is installed, an unscoped
read RAISES UnscopedSecretError instead of falling back to os.environ — a
missed/new call site crashes loudly at that line rather than leaking a
cross-profile value. Genuinely-global vars (HERMES_*, PATH, kanban paths,
…) keep reading os.environ via an allowlist. load_env_file/build_profile_
secret_scope parse a profile .env into an isolated dict WITHOUT mutating
os.environ. Off by default => transparent os.getenv behavior.
- hermes_cli/runtime_provider.py: all credential/provider/base-url reads go
through _getenv -> get_secret.
- agent/credential_pool.py: env fallbacks route through get_secret (the
~/.hermes/.env-first preference is preserved and already profile-correct via
the home override).
- tools/mcp_tool.py: MCP config interpolation resolves through
get_secret, so a server's picks up the routed profile's value.
- gateway/run.py: set_multiplex_active() at GatewayRunner init; per-turn .env
reload is a no-op for credentials in multiplex mode (secrets come from the
scope, not global env); _profile_runtime_scope context manager combines the
HERMES_HOME override + secret scope; _run_agent wraps _run_agent_inner in
that scope (resolved via _resolve_profile_home_for_source) when multiplexing.
Propagates into the agent worker thread for free via the existing
copy_context() in _run_in_executor_with_context.
Tests: 13 unit (fail-closed, scope isolation, global allowlist, .env parsing
without environ mutation) + 7 E2E (runtime_provider + MCP interpolation prove
two profiles isolated, unscoped read raises, globals still read environ).
* feat(mcp): raise default tool-call timeout 120s -> 300s
Port from openai/codex#28234. Long-running MCP tools (web fetches,
sandboxed builds, deep-research servers) routinely exceed 120s, causing
spurious timeout failures. Codex bumped its default MCP tool timeout from
120 to 300 for the same reason.
- _DEFAULT_TOOL_TIMEOUT 120 -> 300 in tools/mcp_tool.py (per-server
'timeout' config override unchanged)
- update test_default_timeout assertion
- document the default in mcp-config-reference.md
* refactor: remove agent-callable send_message tool
The agent should not decide on its own to fire off cross-platform
messages or reactions. Outbound platform messaging is handled outside
the agent loop — cron delivery, the gateway kanban notifier
(dashboard-toggled), and the `hermes send` CLI.
Removes the model-tool registration only; the send engine in
send_message_tool.py (_send_to_platform, _send_via_adapter,
_parse_target_ref, per-platform _send_* helpers) is kept intact for
those non-agent callers. Drops the now-empty 'messaging' toolset and
its `hermes tools` toggle. Yuanbao DM guidance now points at the
native yb_send_dm tool.
* feat(cli): add --safe-mode troubleshooting flag
Inspired by Claude Code v2.1.169 (June 2026): run Hermes with all
customizations disabled to isolate setup problems from product bugs.
--safe-mode implies --ignore-user-config and --ignore-rules, and
additionally skips plugin discovery (hermes_cli/plugins.py) and MCP
server loading (tools/mcp_tool.py) via the internal HERMES_SAFE_MODE
env bridge.
* fix(desktop): keep composer usable during reconnect
Port from anomalyco/opencode#31271: only call tools/list when the server
advertises the 'tools' capability in InitializeResult.capabilities.
Previously, _discover_tools() unconditionally called session.list_tools()
right after initialize. Prompt-only / resource-only servers (which omit
the tools capability per the MCP spec) raise McpError(-32601 Method not
found), which aborted the connection — burning all 3 initial-connect
retries and permanently failing the server even though its prompts and
resources were perfectly usable. The 180s keepalive had the same problem:
it probed with list_tools(), so even a successfully connected prompt-only
server would be torn down on the first keepalive cycle.
Changes:
- MCPServerTask._advertises_tools(): capability check with a legacy
fallback (no captured InitializeResult -> behave as before)
- _discover_tools(): skip tools/list for non-tool servers
- keepalive: use the universal ping request for non-tool servers
- _refresh_tools(): guard against tools/list_changed from non-tool servers
E2E verified with a real stdio prompt-only FastMCP-style server: on main
it fails all 3 connection attempts with Method-not-found; with this fix
it connects, lists prompts, answers ping keepalives, and shuts down
cleanly.
* fix(mcp): propagate HERMES_HOME override onto the MCP event loop
Closes the known limit documented in #44007: tasks scheduled via
run_coroutine_threadsafe are created INSIDE the MCP loop thread, so they
copy that thread's context — a per-request profile scope (dashboard
?profile= endpoints, e.g. the MCP 'Test server' probe) silently vanished
for anything resolving get_hermes_home() inside the coroutine. Most
visible symptom: OAuth token-store paths (HERMES_HOME/mcp-tokens/)
resolved against the process home instead of the selected profile, so
testing an OAuth MCP cross-profile read the wrong tokens.
_run_on_mcp_loop now wraps scheduled coroutines with the caller's
context-local override (_wrap_with_home_override): set inside the task's
own context on the loop, reset on completion — task-local, so concurrent
calls carrying different scopes don't interfere, and the loop thread's
default context stays untouched. No-op (coroutine passes through
unwrapped) when no override is active, i.e. every non-dashboard caller.
web_server's probe comment updated from 'known limit' to 'covered'.
Tests: override propagation (direct + factory form), OAuth token-path
resolution on the loop, loop-context cleanliness after scoped calls,
no-op passthrough. 225 green across mcp_tool + unification suites.
* test(mcp): concurrent different-scope calls don't interfere
get_mcp_status() treated every non-connected server as a failure, so a
server configured with enabled: false rendered as red '— failed' in the
startup banner even though it was intentionally off. Add a 'disabled'
field derived from the enabled flag and render disabled servers dim as
'— disabled' instead.
Reworks the content-type preflight so a misconfigured HTTP MCP url (a web-app
root serving HTML) fails in <1s instead of hanging the full 60s connect_timeout
— and does so non-retryably, which neither original PR achieved.
- Allow-list detection (application/json, text/event-stream) instead of a
text/html-only denylist — catches text/plain, application/xml, etc.
- New NonMcpEndpointError(ConnectionError); run() catches it in the same
top-level fast-fail block as InvalidMcpUrlError, so it returns before the
reconnect-backoff loop (truly non-retryable) and the probe runs once, not
on every reconnect.
- Probe runs on its own httpx client OUTSIDE the SDK anyio task group, so the
error propagates as itself rather than wrapped in an ExceptionGroup (the
trap that made the in-SDK event-hook approach a no-op).
- Forwards ssl_verify + client_cert + headers; HEAD->GET fallback on 405/501;
best-effort pass-through on missing content type, non-2xx, and network
errors; skips SSE transport. CancelledError is never swallowed.
- Replaces the malformed test file (which never imported the real method and
failed CI) with 21 tests driving the actual _preflight_content_type against
a real local HTTP server, plus full run() integration verifying <1s
non-retryable failure.
Co-authored-by: liuhao1024 <sunsky.lau@gmail.com>
Co-authored-by: uzunkuyruk <egitimviscara@gmail.com>
A misconfigured MCP server URL that returns text/html (e.g. pointing at
a web app root instead of an MCP endpoint) causes the MCP SDK to block
for the full connect_timeout (default 60 s) before surfacing
CancelledError.
Add a lightweight HEAD pre-flight check that detects text/html responses
in ≤5 s and raises ConnectionError with an actionable message. Non-HTML
responses, missing headers, and network errors pass through silently so
the normal MCP handshake proceeds unaffected.
Fixes#36052
PAIN BEFORE:
Inside _handle_auth_error_and_retry() (a sync function that runs on the MCP
event loop thread), there was a blocking polling loop:
while time.monotonic() < deadline:
if srv.session is not None and srv._ready.is_set():
break
time.sleep(0.25) # BLOCKS THE ENTIRE EVENT LOOP
Since _handle_auth_error_and_retry is invoked from tool handlers that run ON
the MCP event loop, time.sleep(0.25) blocked ALL concurrent MCP operations
(including other tools, keepalive heartbeats, OAuth refreshes) for 250ms per
iteration. With a 15-second deadline, worst case = 60 * 250ms = 15 seconds
of fully blocked concurrency.
WHAT WAS FIXED:
Extracted the blocking poll into an async helper _await_ready() that uses
asyncio.sleep(0.25) (non-blocking), and runs it via _run_on_mcp_loop().
_run_on_mcp_loop() properly awaits the coroutine on the event loop without
blocking the caller's thread. Added exception handling around the poll so
stuck reconnects still fall through to the error path.
The sync _handle_auth_error_and_retry now:
1. Fires reconnect signal (threadsafe)
2. Calls _run_on_mcp_loop(_await_ready(), timeout=15) — non-blocking
3. Returns; the event loop handles the polling
File: tools/mcp_tool.py
Lines: _handle_auth_error_and_retry() (~1886-1920)
Found by: exhaustive multi-pass audit (10 strategies, 1901 files, 913K lines)
The orphan reaper for stdio MCP subprocesses only tracked the direct child
PID spawned by ``stdio_client`` (e.g. ``openclaw mcp serve``). When that
wrapper itself spawned a helper (``claude mcp serve``) and then exited, the
helper reparented to ``systemd --user`` and survived shutdown.
The MCP SDK already spawns stdio children with ``start_new_session=True``,
so the wrapper is its own pgroup leader and same-pgroup descendants are
reachable via ``killpg``. Capture the pgid at spawn time and reap via
``killpg(pgid, sig)`` so reparented grandchildren are reaped alongside the
direct child, even after the wrapper itself exits. Falls back to per-pid
``os.kill`` on Windows or when no pgid was recorded.
Fixes part 2 (orphan ``claude mcp serve``) of #23799. Part 1 (per-invocation
respawn) was confirmed by the reporter to be an environmental artifact, not
a code bug.
asyncio.gather(return_exceptions=True) captures CancelledError as a
BaseException value. The previous isinstance(result, Exception) check
missed CancelledError, silently dropping it without logging.
Since Python 3.9, CancelledError is a BaseException subclass (not
Exception). This one-line change ensures all failure types from MCP
server connections are properly logged.
FixesNousResearch/hermes-agent#34443
When the Hermes Docker image runs an stdio MCP server configured with an
explicit env.PATH that omits /usr/local/bin (a common pattern when users
hand-author PATH for sandboxing), the MCP env-filter passes that narrow
PATH straight through to the subprocess. _resolve_stdio_command's
fallback for bare 'npx' / 'npm' / 'node' commands only checked
$HERMES_HOME/node/bin/ and ~/.local/bin/, so execvp() failed with
'[Errno 2] No such file or directory: npx' on every Node-based stdio
MCP server (Railway, Anthropic, GitHub Copilot, etc.).
The naive workaround — symlink /usr/local/bin/npx into the user's PATH —
fails one layer deeper because npx's shebang re-execs /usr/bin/env node
and node also lives at /usr/local/bin/node.
Fix: add /usr/local/bin/<cmd> as a third candidate in the fallback list.
This is the canonical install location for Node on:
- Linux from-source builds
- the upstream node:bookworm-slim image, which the Hermes Docker
image copies node + npm + corepack from since #4977 (the Node 22 LTS
refactor that exposed this)
- macOS Homebrew on Intel
Because the resolver already calls _prepend_path(resolved_env, command_dir)
after locating the command, /usr/local/bin gets prepended to the env's
PATH automatically, which also fixes the second-layer shebang failure
(npx-cli.js can now find node).
Scope is intentionally narrow: the fix activates only when the bare
command isn't otherwise locatable through the user's PATH. Users who
explicitly narrowed PATH for a non-Node MCP server see no change in
behavior.
Tested:
- tests/tools/test_mcp_tool_issue_948.py: new test
test_resolve_stdio_command_falls_back_to_usr_local_bin (mirrors the
existing hermes-node-bin fallback test)
- Full MCP test suite: 254/254 pass across 7 test files
- E2E against a freshly-built Docker image: reproduced the original
failure mode (env.PATH=/opt/data/bin:/usr/bin:/bin), confirmed the
resolver returns /usr/local/bin/npx and prepends /usr/local/bin to
PATH; subprocess.run of the resolved command prints '10.9.8' and
exits 0 with empty stderr
- Negative E2E on the host (where Node is already on PATH via mise):
resolver still hits the mise install dir, /usr/local/bin candidate
is not consulted, PATH is unchanged
Adds first-class `client_cert` / `client_key` config keys so MCP servers
behind mTLS work without an external TLS-terminating proxy. Resolves
inbound community question (Jeremy W.).
Schema (per `mcp_servers.<name>`, HTTP/SSE only):
- `client_cert: "/path/to/combined.pem"` — single PEM with cert + key
- `client_cert: "/path/to/cert"` + `client_key: "/path/to/key"` — separate
- `client_cert: [cert, key]` or `[cert, key, password]` — list form,
with optional passphrase for encrypted keys
Paths support `~` expansion. Missing files raise a server-scoped
`FileNotFoundError` at connect time rather than failing later with an
opaque TLS handshake error.
Wiring:
- New SDK HTTP path (mcp >= 1.24): `cert=` on the user-owned
`httpx.AsyncClient` alongside the existing `verify=` handling.
- SSE path: routed through an `httpx_client_factory` that wraps the
SDK's defaults (follow_redirects=True) and layers `verify` + `cert`
on top. The factory is only injected when needed, so the SDK's
built-in `create_mcp_http_client` keeps being used in the default
case.
- Deprecated mcp<1.24 path left untouched — that SDK's
`streamablehttp_client` signature doesn't expose `cert`, and adding
it would be dead code.
Also documents the previously-undocumented `ssl_verify` key (bool or
CA bundle path) in the MCP config reference.
Tests:
- `tests/tools/test_mcp_client_cert.py` (new, 19 tests):
- `_resolve_client_cert` helper: all three input forms, `~` expansion,
missing-file and validation errors.
- HTTP transport: `cert=` forwarded into `httpx.AsyncClient` for
string and tuple forms; absent when unset; missing-file error
propagates.
- SSE transport: factory only injected when cert or non-default
verify is set; factory applies cert, custom CA bundle, and
preserves `follow_redirects=True` + forwarded headers/auth.
- Existing tests: 200/200 in `test_mcp_tool.py` + `test_mcp_sse_transport.py`
still pass.
