The server-side timer added in round 9 applied to every /api/fetch
request. But that route carries MCP traffic as well as OAuth work, so a
Streamable HTTP tool call that legitimately withholds its response
headers past the budget was aborted there — reintroducing on the
backend exactly the regression exemptMcpEndpoint prevents on the
client, and reporting it as an OAuth timeout besides.
The caller now decides. `withOAuthRequestTimeout` stamps its budget on
the RequestInit it hands down, `createRemoteFetch` reads it back and
puts it in the /api/fetch envelope, and the route applies a timer only
when one is present — so an exempt MCP request, which never gets an
init of its own, is bounded by nothing.
The carrier is a WeakMap keyed on the init rather than a header:
serializeRequest copies request headers verbatim into the payload and
the route re-sends them to the authorization server, so a marker header
would leak to a third party. It needs no cast onto RequestInit and is
collected with the object.
The `fetchTimeoutMs` option from round 9 is gone — the deadline now
lives in exactly one place, the client wrapper, which is also what
makes the 504 marker honest: only a request the OAuth wrapper bounded
can produce one.
Ten tests: the stamping and its rounding, nothing stamped on an exempt
call or an init that never went through the wrapper, the envelope
carrying the budget (and not a header), its omission on both exempt and
direct calls, and at the route the 504 marker, no deadline without one,
and a non-numeric deadline ignored. The no-deadline case is verified by
mutation: an unconditional timer makes it fail.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YFnM6RqB4nXqNysgUYmjmq
Signed-off-by: cliffhall <cliff@futurescale.com>
Copying url/redirected/type onto the rebuilt response as enumerable own
properties changed what a consumer sees: `Object.keys`, object spread
and `JSON.stringify` are all affected. Which answer is correct turns
out to be the host's business — under the Fetch standard these are
prototype getters with no own enumerable key, while happy-dom defines
them as own enumerable data properties — so the descriptor is copied
from the freshly built Response rather than either answer being
hardcoded. The test compares against a baseline built in the same
runtime for the same reason.
Three comments still described the transport fetch as unbounded, which
round 11 changed:
- the wrapper's own docblock said it must never wrap the transport,
obscuring that isExempt is what makes doing so safe;
- the auth-chain comment in inspectorClient repeated it;
- buildEffectiveAuthFetch's docblock said transport-internal discovery
is not covered by a deadline.
All three now state the real distinction — both chains are bounded, and
they differ only in that the transport chain exempts the MCP endpoint —
and the docblock says why reusing the transport chain here would be
wrong rather than merely different.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YFnM6RqB4nXqNysgUYmjmq
Signed-off-by: cliffhall <cliff@futurescale.com>
The transport chain carried the SDK's own OAuth work — the discovery it
runs from inside the transport on the 401/refresh path — and that leg
was left to the SDK's incidental per-request timeout, reporting a bare
`Request timed out` naming no endpoint. On a direct (non-proxied) path
the /api/fetch backstop cannot reach it either.
`withOAuthRequestTimeout` takes an optional `isExempt` predicate; an
exempt request passes through completely untouched — no deadline, no
signal, and no body buffering, which is what a stream needs.
`exemptMcpEndpoint` exempts the MCP endpoint by origin + pathname, and
FAILS OPEN: no server URL, or either side unparseable, means exempt.
The errors are not symmetric. Bounding what should not be bounded
severs a long-running tool call withholding its headers, or an SSE
body; failing to bound leaves the SDK's timeout as the backstop it
already was.
Two test corrections, both real:
- The metadata-preservation case asserted url/redirected/type against a
synthetic Response, whose values are the rebuild's own defaults — so
it stayed green with the defineProperty loop deleted. It now seeds
non-default values first; verified by mutation that removing the loop
makes it fail.
- Two signal assertions compared against the controller rather than
`request.signal`. The Fetch standard gives a Request a dependent
signal, so those encoded non-standard identity.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YFnM6RqB4nXqNysgUYmjmq
Signed-off-by: cliffhall <cliff@futurescale.com>
A deadline enforced by the backend could not arrive as an
OAuthRequestTimeoutError: /api/fetch serialized it as a 500 and
createRemoteFetch turned that into a plain Error, so every instanceof
check downstream was false — including the one that lets a stalled
probe escape withRfc8414OidcCompat. That matters most where no
client-side wrapper exists to have fired first: the discovery the SDK
runs from inside the transport. The route now answers 504 with a typed
marker (OAUTH_TIMEOUT_WIRE_CODE plus url and timeoutMs) and
createRemoteFetch reconstructs the error from it, guarded by a shape
check so an upstream's own JSON cannot forge one.
The route's deadline becomes a `fetchTimeoutMs` option defaulting to
the shared constant, so the backstop can be proven to fire in
milliseconds instead of thirty seconds of wall clock — and because a
very slow authorization server is a legitimate reason to want a longer
one.
The rounding rationale was wrong: setTimeout accepts a fractional delay
and truncates it (verified on Node 26); ERR_OUT_OF_RANGE is
AbortSignal.timeout's behaviour, which this wrapper never calls. The
rounding stays, for the reason that is actually true — the budget is
interpolated into the message and exposed as timeoutMs, and a
performance.now() budget would otherwise report 1000.4000000953674ms.
Also drops a sentence in the discarded-stream test that contradicted
the qualification above it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YFnM6RqB4nXqNysgUYmjmq
Signed-off-by: cliffhall <cliff@futurescale.com>
Three findings, all real.
`arrayBuffer()` hands back the decoded entity body, so the rebuilt
response was carrying the upstream `content-encoding` and the
compressed `content-length` — a gzipped metadata document came back as
plain JSON bytes still claiming gzip and the wrong size, visible in the
Network capture. Both headers are deleted now, as `responseWithBody` in
endpointOverrides.ts already did for the same reason.
The "why a race, and not just the signal" rationale described a world
this PR had since changed: the signal does now reach the backend's
outbound fetch. The module doc and three implementation comments are
rewritten to say what the race is actually still for — a fetchFn that
ignores AbortSignal, and a backend that is itself wedged — rather than
a proxy hop that no longer drops it.
The backend cancellation path had only mock-level coverage. A
route-level test drives /api/fetch at an upstream that accepts and never
answers, aborts the browser side, and asserts the upstream observes its
connection closing. Verified by mutation: dropping `signal` from the
route's outbound fetch makes it time out rather than pass.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YFnM6RqB4nXqNysgUYmjmq
Signed-off-by: cliffhall <cliff@futurescale.com>
Both findings are on the caller-signal handling added in round 1:
- `"signal" in init` treated a member present as `undefined` as an
explicit override. `RequestInit` is a WebIDL dictionary, where such a
member converts as absent — so `{ ...base, signal: undefined }`, which
is what a spread over an options object with no signal produces, was
clearing a Request's embedded signal instead of inheriting it. Only a
non-`undefined` value overrides now; an explicit `null` is still the
genuine no-signal case.
- An already-aborted caller signal rejected the race, but
`Promise.race` still evaluated `fetchFn(...)`, so on the
signal-dropping proxy path the OAuth request went out anyway. It now
short-circuits before anything is constructed or sent, and the
now-unreachable aborted branch inside the race is gone.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YFnM6RqB4nXqNysgUYmjmq
Signed-off-by: cliffhall <cliff@futurescale.com>
Three findings, all real:
- The deadline stopped at the response headers. `fetch` resolves once
headers arrive, so a server that sent headers — or half a JSON
document — and then stalled left the caller's `response.json()`
hanging with nothing watching it. The body is now buffered under the
same race and the response rebuilt around it, preserving `url`,
`redirected` and `type`, which have no constructor option, and
passing `null` for a null-body status.
- The caller's signal was only forwarded, not raced. On the browser's
`createRemoteFetch` path the signal is dropped in flight, so an abort
left the promise pending for the whole budget rather than the outer
cancellation winning as documented. It is raced now, with the
caller's own `reason` preserved, and the listener removed in
`finally` since one caller signal outlives several requests.
- A `Request` carries its signal on the input, not in `init`, so always
passing our own `signal` in `init` silently overrode it. The caller
signal is now derived from the `Request` when `init` has no `signal`
key — and an explicit `null` there still wins, per the fetch spec.
Eight new tests cover each: the stalled body, caller cancellation
against a signal-ignoring fetch, an already-aborted signal, the
Request-embedded signal, the explicit-null override, listener removal,
the rebuilt response's metadata and a null-body status.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YFnM6RqB4nXqNysgUYmjmq
Signed-off-by: cliffhall <cliff@futurescale.com>
Protected-resource-metadata discovery, authorization-server metadata
discovery, dynamic client registration, the token exchange and the
refresh all went out with no AbortSignal at all. Token revocation was
the single exception, and its withDeadline race is the pattern this
generalizes.
Adds core/auth/requestTimeout.ts: withOAuthRequestTimeout wraps a fetch
so every call through it is bounded, composing any caller signal with
AbortSignal.any and racing a timer so the deadline holds even where the
signal is dropped in flight (the browser's remote fetch re-issues the
call to /api/fetch and forwards no signal). The rejection is an
OAuthRequestTimeoutError naming the URL, so a stall says which endpoint
stalled rather than riding the SDK handshake timeout and reporting
"Request timed out".
Applied inside InspectorClient.buildEffectiveAuthFetch rather than to
this.fetchFn, because the transport is handed this.fetchFn directly and
a deadline on a Streamable HTTP / SSE response would sever the stream it
is supposed to hold open. Also applied to the CLI's storedAuthFetch,
which calls SDK discovery directly and so has nothing else bounding it.
Closes#2319
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YFnM6RqB4nXqNysgUYmjmq
Signed-off-by: cliffhall <cliff@futurescale.com>
