mcp 2.0.0 implements MCP revision 2026-07-28 and makes three breaking
changes Hermes sits on top of: `mcp.server.fastmcp` is gone, every model
field is renamed to snake_case (camelCase survives only as a
serialization alias, which pydantic does not expose to attribute
access), and the SDK's own HTTP stack moved from `httpx` to `httpx2`.
Bump the pin across the dev/mcp/computer-use extras and port the tree:
- `mcp_serve.py` and `agent/transports/hermes_tools_mcp_server.py` move
from `FastMCP` to `mcp.server.MCPServer`, which has the same
decorator/add_tool surface. The hermes-tools server already
synthesised `__signature__` from Hermes' JSON Schema, which is exactly
what 2.0's `add_tool` reads.
- SDK model reads go through `mcp_field(obj, snake, camel)`, which reads
both spellings. A single-spelling read fails *silently* on the other
generation — empty tool schemas, dropped structured content, tool
results vanishing from sampling conversations — and `mcp` is an
optional extra users install at their own version.
- `sdk_httpx()` resolves the httpx flavour from the SDK's own transport
module, so objects handed to `streamable_http_client`, the `sse_client`
factory, and the OAuth metadata helpers come from the module the
installed SDK actually imports.
- HTTP support is gated on either streamable-HTTP entry point, not just
the deprecated alias 2.0 removed.
- OAuth: `OAuthClientProvider` lost its `timeout` argument (the
configured `oauth.timeout` now bounds the callback waiter's own poll
loop, where the browser round-trip was always awaited), and
`callback_handler` must return `AuthorizationCodeResult` rather than a
tuple. 2.0 also validates the RFC 9207 `iss` parameter, so the
callback handler and paste fallback capture it.
`mcp`/`mcp-types` 2.0.0 are inside the 14-day `exclude-newer` window, so
two narrow `exclude-newer-package` entries unblock `uv lock`, annotated
for removal on or after 2026-08-11. `httpx2` needs no exemption: 2.7.0 is
already outside the window and satisfies mcp's floor.
Refs #69931
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
* [verified] fix(mcp-oauth): bridge httpx auth_flow bidirectional generator
HermesMCPOAuthProvider.async_auth_flow wrapped the SDK's auth_flow with
'async for item in super().async_auth_flow(request): yield item', which
discards httpx's .asend(response) values and resumes the inner generator
with None. This broke every OAuth MCP server on the first HTTP response
with 'NoneType' object has no attribute 'status_code' crashing at
mcp/client/auth/oauth2.py:505.
Replace with a manual bridge that forwards .asend() values into the
inner generator, preserving httpx's bidirectional auth_flow contract.
Add tests/tools/test_mcp_oauth_bidirectional.py with two regression
tests that drive the flow through real .asend() round-trips. These
catch the bug at the unit level; prior tests only exercised
_initialize() and disk-watching, never the full generator protocol.
Verified against BetterStack MCP:
Before: 'Connection failed (11564ms): NoneType...' after 3 retries
After: 'Connected (2416ms); Tools discovered: 83'
Regression from #11383.
* [verified] fix(mcp-oauth): seed token_expiry_time + pre-flight AS discovery on cold-load
PR #11383's consolidation fixed external-refresh reloading and 401 dedup
but left two latent bugs that surfaced on BetterStack and any other OAuth
MCP with a split-origin authorization server:
1. HermesTokenStorage persisted only a relative 'expires_in', which is
meaningless after a process restart. The MCP SDK's OAuthContext
does NOT seed token_expiry_time in _initialize, so is_token_valid()
returned True for any reloaded token regardless of age. Expired
tokens shipped to servers, and app-level auth failures (e.g.
BetterStack's 'No teams found. Please check your authentication.')
were invisible to the transport-layer 401 handler.
2. Even once preemptive refresh did fire, the SDK's _refresh_token
falls back to {server_url}/token when oauth_metadata isn't cached.
For providers whose AS is at a different origin (BetterStack:
mcp.betterstack.com for MCP, betterstack.com/oauth/token for the
token endpoint), that fallback 404s and drops into full browser
re-auth on every process restart.
Fix set:
- HermesTokenStorage.set_tokens persists an absolute wall-clock
expires_at alongside the SDK's OAuthToken JSON (time.time() + TTL
at write time).
- HermesTokenStorage.get_tokens reconstructs expires_in from
max(expires_at - now, 0), clamping expired tokens to zero TTL.
Legacy files without expires_at fall back to file-mtime as a
best-effort wall-clock proxy, self-healing on the next set_tokens.
- HermesMCPOAuthProvider._initialize calls super(), then
update_token_expiry on the reloaded tokens so token_expiry_time
reflects actual remaining TTL. If tokens are loaded but
oauth_metadata is missing, pre-flight PRM + ASM discovery runs
via httpx.AsyncClient using the MCP SDK's own URL builders and
response handlers (build_protected_resource_metadata_discovery_urls,
handle_auth_metadata_response, etc.) so the SDK sees the correct
token_endpoint before the first refresh attempt. Pre-flight is
skipped when there are no stored tokens to keep fresh-install
paths zero-cost.
Test coverage (tests/tools/test_mcp_oauth_cold_load_expiry.py):
- set_tokens persists absolute expires_at
- set_tokens skips expires_at when token has no expires_in
- get_tokens round-trips expires_at -> remaining expires_in
- expired tokens reload with expires_in=0
- legacy files without expires_at fall back to mtime proxy
- _initialize seeds token_expiry_time from stored tokens
- _initialize flags expired-on-disk tokens as is_token_valid=False
- _initialize pre-flights PRM + ASM discovery with mock transport
- _initialize skips pre-flight when no tokens are stored
Verified against BetterStack MCP:
hermes mcp test betterstack -> Connected (2508ms), 83 tools
mcp_betterstack_telemetry_list_teams_tool -> real team data, not
'No teams found. Please check your authentication.'
Reference: mcp-oauth-token-diagnosis skill, Fix A.
* chore: map hermes@noushq.ai to benbarclay in AUTHOR_MAP
Needed for CI attribution check on cherry-picked commits from PR #12025.
---------
Co-authored-by: Hermes Agent <hermes@noushq.ai>
Gille