3 Commits

Author SHA1 Message Date
青榆牧
a94b2d8897
feat(mcp): map request-scoped secrets to MCP HTTP/SSE headers (#5010)
* feat(mcp): map request-scoped secrets to HTTP/SSE headers

`user_auth` binds a credential to a configured DeerFlow user, so a caller
that picks the credential per request — a multi-tenant gateway, a per-run
API key, one shared MCP server fronting several environments — had to
register one MCP server entry per credential.

Add a declarative `mcpServers.<server>.headers_from_context` block mapping
HTTP header names to keys of the run request's `config.context.secrets`
carrier. A new built-in interceptor resolves the mapping on every tool call
and rewrites those headers, mirroring `user_scoped_auth`. The config file
stores names only, never a credential, so the Gateway returns the block
unmasked.

Registered after OAuth and `user_auth` in the interceptor chain: the later
interceptor runs closer to the transport, and the value chosen for this one
request is the most specific, so it wins. Fail-closed by default — a mapped
key missing from the request raises a `ToolException` naming only that key,
because falling back to the server's discovery credential would send one
tenant's call under another tenant's authority. `on_missing: "passthrough"`
opts out.

Durable background tasks are excluded: `McpTaskToolCaller` drives status and
cancel polls after the Agent run ends, where no run context exists, so the
fail-closed interceptor would deny every poll. Those calls keep using
server-level credentials, and a server declaring both `headers_from_context`
and `task_toolsets` now logs a warning.

Also corrects the custom-interceptor example in docs/MCP_SERVER.md (and the
matching claim in skills/AGENTS.md), which read request secrets from
`langgraph.config.get_config()["context"]`. That key is `None` inside a tool
call — the run context rides the LangGraph runtime, not the RunnableConfig
propagated to child runnables — so interceptors written from that example
never saw a value. The example now reads `request.runtime`, and
tests/test_mcp_context_headers.py pins LangGraph's runtime-injection rule by
driving a real langchain-mcp-adapters tool through a real graph with the
ambient-runtime fallback disabled.

Closes #5005

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(mcp): resolve credential headers case-insensitively, carry them on durable submit

Review follow-ups on `headers_from_context`.

HTTP field names are case-insensitive, but every dict on the path to the wire
is not: `build_server_params` copies the operator's static `headers` spelling
verbatim, and langchain-mcp-adapters merges interceptor overrides into the
connection with a plain `{**connection_headers, **override_headers}` splat. A
static `authorization` and an injected `Authorization` therefore both reached
httpx as separate field lines, and a server reading the field with a
single-value accessor got the static discovery credential — inverting the
documented `headers` < `oauth` < `user_auth` < `headers_from_context`
precedence and running a per-request call under the shared credential.

Normalizing inside the interceptor cannot fix that on its own: the adapter
builds the request with `headers=None`, so an interceptor never sees the
connection's static headers and cannot displace them however it spells its own
key. A new `mcp/headers.py::apply_header_overrides` therefore drops any key
differing only in case and emits the spelling the connection already uses.
Applied to `headers_from_context`, `user_auth`, the OAuth interceptor, the
OAuth discovery-header write, and the durable-task connection merge, which all
carried the same collision. `headers_from_context.headers` now also rejects one
header mapped under two spellings at config load, in both the harness model and
the Gateway mirror.

Durable submit now carries the mapped headers, as docs/MCP_SERVER.md already
promised. `McpTaskToolCaller` disabled the interceptor for the whole caller, but
that caller serves submit as well as the polls, and submit is awaited inline
inside the Agent's tool call — where the run's LangGraph runtime is still the
ambient contextvar, so no secret has to be threaded through `TaskSubmitRequest`
or reach durable storage. The caller builds one chain and keeps a second view of
it without the context-headers interceptor; `call_tool` takes
`request_scoped_headers`, set only by `OrdinaryMcpTaskDriver.submit`. Status and
cancel keep server-level credentials, so background polls still cannot fail
closed, and the startup warning now describes the half it actually covers.

`_merge_preserving_secrets` restores masked extras inside `headers_from_context`
instead of writing the `***` sentinel back over the stored value, matching the
treatment `user_auth` extras and server-level extras already get; extras a PUT
omits carry over as well, while the declared mapping still replaces verbatim so
a round trip can remove an entry. `extra="allow"` plus name-based sensitivity
detection means the usual casualty is a name-valued key such as `tokenHeader`,
not only a credential.

The existing override test seeded the static header onto `request.headers`,
which production never does, so it modelled a merge that really happens one
layer down; the new tests drive a real adapter tool through a real connection
and assert on the headers the session is opened with, and the durable-submit
test runs through a real tool node with no runtime patching.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(mcp): reject case-insensitive duplicate static header names

* fix(mcp): preserve omitted headers_from_context fields on partial updates

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
2026-08-27 10:42:42 +08:00
ajayr
7e95bef2e7
feat(mcp): per-user credential injection for shared MCP servers (#4868)
* feat(mcp): per-user credential injection for shared MCP servers

A single HTTP/SSE MCP server entry can now serve several users, each
authenticated to the remote service with their own credential. A server
opts in with a user_auth block mapping user ids to credential header
values ($ENV_VAR references supported):

  "user_auth": {
    "header": "Authorization",
    "users": { "<user-id>": "$SERVICE_TOKEN_ALICE" }
  }

The built-in user-scoped auth interceptor resolves the authenticated
runtime user on every tool call (request runtime -> ambient LangGraph
runtime -> auth config -> request-scoped user ContextVar) and rewrites
the configured header via request.override(), the same per-call
mechanism as the OAuth interceptor. It registers after OAuth in the
shared assembly so its per-user value wins the header when a server
declares both. The entry's static headers are used only for startup
tool discovery.

Fail-closed by default: an unmapped user - including the anonymous
default-user fallback - or a credential whose env reference resolved
empty gets an actionable ToolException instead of another user's
credential; on_missing: "passthrough" opts out per server. Combined
with the existing per-(user, thread) MCP session scoping this gives
credential isolation on shared servers.

Gateway API: user_auth.users values are masked in GET responses, and
PUT round-trips preserve stored credentials for masked values (same
contract as env/headers/oauth secrets); a masked value for a user id
not already stored is rejected.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(mcp): address review — preserve stored user_auth sub-fields on partial PUT, warn-and-skip stdio, allow extras

Review findings from #4868:

1. A partial user_auth payload (e.g. {"enabled": false}) merged to
   users={} and default on_missing, irreversibly wiping stored
   credentials on PUT. The merge is now sub-field-aware via
   model_fields_set — omitted sub-fields carry the stored values, an
   explicitly sent users map still replaces (so full-round-trip removal
   works), masked values still swap back for stored credentials.

2. user_auth on a stdio server was a silent no-op: rewritten headers go
   to call meta, never a transport header, while deny errors still fired.
   The interceptor builder now warns and skips non-sse/http servers,
   matching the tool_call_timeout transport-mismatch convention.

3. McpUserScopedAuthConfigResponse now allows extra keys like the
   harness-side model, and extras survive masking and merge, matching
   the server-level model_extra handling.

Adds four regression tests (partial-PUT preservation, explicit-map
replacement, extras round-trip, stdio warn-and-skip).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(mcp): reject blank user_auth.header at the gateway

A blank header passed the gateway response model, was persisted, then
failed the harness-side ExtensionsConfig validator on reload — the PUT
returned 500 after the write and every later config load/startup failed
until the file was hand-edited. Mirror the harness non-blank validator
on McpUserScopedAuthConfigResponse so the PUT fails with 422 before
anything is written.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* style: ruff format extensions_config.py

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(mcp): harden the trust chain and masking around user-scoped credential selection

Address review round 4:
- Scrub client-supplied user_id from run context/configurable for
  external callers in inject_authenticated_user_context, before every
  early return, and restamp only from request.state.user. Now that
  user_id selects which user's credential user-scoped MCP auth injects,
  a forged value must not survive any future path that skips the
  restamp. Internal callers (IM channels, scheduler) keep supplying
  end-user identity as before (PR #3294 contract). Regression tests pin
  both the scrub and that a forged body.context.user_id can never
  resolve as another user through merge + inject ordering.
- Include the caller's own resolved user id in the fail-closed deny
  message so operators can copy the exact users key (it differs by
  deployment path), and document the key formats in the mcp.mdx doc.
- Mask sensitive extra keys inside user_auth on GET like server-level
  extras, and swap masked sentinels back for stored values on PUT via
  _merge_extra_value_preserving_masked.
- Extract the interceptor wrap loop into compose_tool_interceptors and
  pin the security property functionally: an OAuth interceptor that
  actually sets Authorization loses the final header to the per-user
  credential through the same composition the session-pool path uses.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
2026-08-23 15:16:04 +08:00
Aari
47b258ebd7
feat(mcp): add ordinary durable task driver (#4690)
* feat(mcp): add durable task runtime foundation

* fix(chart): sync embedded config version

* fix(mcp): isolate task polls during shutdown

* feat(mcp): track consecutive poll errors on mcp_tasks

poll_attempt_count grows on every claim (successful polls included), so it
cannot drive a failure backoff without misjudging normal long tasks. Add
consecutive_poll_error_count: incremented when a claim is released after a
poll error, reset to zero by any applied snapshot. The backoff/terminal
policy that consumes it lands with the first concrete driver.

* fix(mcp): harden durable task lifecycle

* feat(mcp): add ordinary durable task driver

* test(mcp): address durable task review feedback

* fix(mcp): preserve submit tool descriptions

* fix(mcp): bound remote task calls

* fix(mcp): bound persisted task payloads

* fix(mcp): preserve task tool error details

* fix(mcp): enforce durable task boundaries

* test(mcp): cover task config snapshot lifecycle

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
2026-08-15 14:26:38 +08:00