The imperative ctx.sample()/ctx.list_roots() stay removed, but both
capabilities survive as input-required requests, as tests/conformance
exercises on 2026-07-28. Direct LLM calls remain the recommendation for
generation; roots has no round-trip-budget objection.
A proxy has no back-channel to the real user, so driving a backend ask inside
it failed outright. Surface it as a result for the parent, as ProxyTool does.
Partial fulfillment means two in-flight updates can carry different answers,
so acknowledging the one that loses the update lock stranded the task on a key
the client had already sent.
Prompt and resource asks carry no content, so caching one stored an empty
result and the client never saw the question. Bypass the cache on
continuation legs and return asks unwrapped, as tool calls already did.
Keep the final outstanding input marker until the next task leg is durable,
so a racing tasks/get cannot read a parked leg as complete. Let resources and
resource templates return InputRequiredResult like tools and prompts. Identify
parked requests by their question rather than sort order.
Deletes fastmcp/server/sampling/, Context.sample/sample_step/list_roots, and
FastMCP(sampling_handler=). The proxy's handshake-era relay now reaches the
front session through the SDK directly.
* Honor OAuth application_type in DCR (SEP-837)
* Simplify web redirect check per ruff SIM103
* Enforce application_type over HTTP, at auth time, and tighten native scheme rules
Recover the DCR application_type the SDK RegistrationHandler drops (P1), enforce the stored type on the authorization redirect path (P2), restrict native to loopback http + custom schemes (P2), and document the web/native rules (P2).
* Fix loopback range detection and use a positive scheme allowlist
Classify loopback hosts with ipaddress.is_loopback so all of 127.0.0.0/8 counts (a web client could bypass the non-loopback rule with 127.0.0.2). Replace the NON_REDIRECT_NETWORK_SCHEMES denylist with STANDARD_URI_SCHEMES: native now accepts only https, loopback http, and unregistered private-use schemes per RFC 8252, so smb/smtp/nfs and other unlisted standard schemes no longer pass.
* Vendor the IANA scheme registry and consolidate the loopback classifier
Replace the hand-picked STANDARD_URI_SCHEMES with a vendored snapshot of the IANA URI scheme registry (423 schemes), so registered transports nobody enumerated (coap, coaps, stun, turn, mqtt) fail closed instead of passing as private-use. Delete the stale duplicate _is_loopback_host in oauth_proxy/models.py and reuse the ipaddress-based classifier from redirect_validation, restoring loopback port flexibility across all of 127.0.0.0/8.
* Treat the reserved localhost namespace and absolute host forms as loopback
RFC 6761 6.3 reserves the whole localhost namespace for the local machine, so app.localhost and localhost. are loopback just as much as localhost. Previously a web client could register https://app.localhost/callback and bypass the non-loopback rule, while native clients were wrongly refused legitimate http://app.localhost:3000 dev callbacks. The suffix test is anchored on a leading dot so localhost.evil.com and notlocalhost stay non-loopback.
* Narrow scope: drop native scheme classification, keep the web rule
Registry membership cannot separate app-dispatch schemes from network transports (vscode is registered because it is an app scheme), so classifying a native client's scheme rejected callbacks that real MCP clients need. Remove the vendored registry and the private-use test; native now accepts any scheme outside the unsafe set, with cleartext http still limited to loopback. Also reject web registrations that omit redirect_uris rather than storing an unusable localhost placeholder.
* fix : canonical mime type mapping from formats to remove inconsistency
* Apply ruff format to _get_mime_type
---------
Co-authored-by: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
* Signal component-level scope shortfalls as insufficient_scope (SEP-2350)
* Fix ty type narrowing in scope step-up test
* Respect check short-circuit when reporting scope shortfall (P2)
* Report union of unmet scopes and document step-up contract
* Aggregate scope shortfall across the AuthMiddleware chain
* Stop chain scope aggregation at the first unevaluated gate
* Unpublish v4 development notes; prep docs for beta 1
* Nest development notes under dev-docs/
* Rewrite site-root links in dev notes as absolute URLs for GitHub rendering
2.1.216 regressed the bubblewrap sandbox the action wraps Bash in when
allowed_non_write_users is set, so every command failed and triage applied
zero labels while reporting success. Also fail the triage job on sandbox
errors, which the existing denial guard could not see.
The example called proxy.with_namespace("remote"), which is not defined
anywhere in the codebase and raises AttributeError. Namespacing a provider
is done via the add_provider() keyword argument.
* Pin burner-redis below the Windows-crashing 0.1.7 release
burner-redis 0.1.7 crashes the interpreter (native fault, no Python traceback)
running the memory:// task backend under pytest-xdist on Windows — reproduced on
GitHub Actions windows-latest via the 'Upgrade checks' workflow, confirmed
absent on macOS/Linux with the identical dependency versions.
pydocket only floors burner-redis at >=0.1.6, so capping pydocket's own version
is not enough: a resolver remains free to pick the newest burner-redis
satisfying that floor. fastmcp-tasks previously pinned pydocket>=0.20.0 with no
upper bound, so a fresh 'pip install fastmcp[tasks]' today can resolve straight
into the broken combination for a real Windows user on the default backend.
Pin burner-redis<0.1.7 directly, which in turn caps pydocket to <0.20.2 (the
last release that doesn't itself require burner-redis>=0.1.7). Verified the pin
holds under both locked and --upgrade (highest) resolution.
* Scope the burner-redis pin to Windows only
burner-redis 0.1.7 is confirmed fine on macOS/Linux (full suite green there with
the identical upgraded dependencies) - only Windows crashes. The previous
unconditional pin blocked every platform from newer pydocket/burner-redis
releases unnecessarily. Add sys_platform == 'win32' to the burner-redis
constraint so only Windows installs are capped.
Verified via uv pip compile --python-platform: macOS/Linux resolve to
burner-redis 0.1.7 / pydocket 0.23.0 (unblocked); Windows resolves to
burner-redis 0.1.6 / pydocket 0.20.1 (still capped).
Server-side completions (@mcp.completion) shipped in #4582 but the
What's New page didn't mention it. Adds it to the authoring-capabilities
cluster with a runnable example and a link to the servers/completions page.
* v4 docs quality pass: fix stale task/era claims, broken links, writing polish
* whats-new: add the client-side protocol negotiation story
The page told the server half of the era story (serves every era) but
never the client half — that a default Client(url) now negotiates the
modern era, where earlier versions pinned the handshake. Completes the
mental model and links to the client negotiation docs.
* Address review: drop 'complete' over-claim; link mounted-state to Session State
* Fix stale Mac/Windows-vs-Linux OAuth key/storage docs
#2223 replaced platform-aware keyring/MemoryStore defaults with
deterministic key derivation and an always-on-disk encrypted store,
but the docs update in that PR missed several spots.
* Fix OIDCProxy doc referring to internal upstream_client_secret name
Codex review: the public OIDCProxy constructor takes client_secret;
upstream_client_secret is only OAuthProxy's internal parameter name.
A task-augmented tools/call returns a CreateTaskResult up through the middleware
chain. Response caching and response limiting assumed a ToolResult and accessed
.content/.wrap(), crashing after the task was already enqueued (a client retry
could duplicate side effects). Both now pass any non-ToolResult through
untouched, alongside the existing InputRequiredToolResult bypass.
Five review fixes. ctx.session_id / get_state / set_state now work in a Docket
worker by falling back to the snapshotted session id. Task management wire calls
(submission, tasks/get/update/cancel) create client spans and propagate trace
context. TasksClientSettings loads .env like DocketSettings, and the docs use
its real env var name. A state-only guard round (request_state, no input
requests) fails with a clear error instead of silently completing wrong.
* Archive v3 docs under /v3 and publish v4 as the primary version
* Label primary docs version v4.0.0 (alpha 1)
* Add What's New in v4 page; fix upgrade-guide phrasing; point banner at What's New
* Rewrite What's New around v4's new capabilities, not the sampling deprecation
* Lead What's New with the SDK v2 engine swap and the SEPs it brings
* State ships now (link Session State); tasks arrive next alpha
* Exclude docs/v3 frozen snapshots from doc-example import validation
