* Remove 3.x-era compatibility shims
* Require response_type in ctx.elicit()
* Name the utilities path for the two non-re-exported auth helpers
* Point sampling handler migration at its submodule
* Document the issuer_url identity change for upgraders
Adds an upgrade note covering the one-time re-authorization, fixes the MultiAuth examples that pointed issuer_url at the upstream IdP, and corrects the OCI docstring.
* Address review: valid docstring example, narrower reauth scope
* Scope the reauth checklist item to token-minting providers
* Add require_roles auth check
* Make role docs runnable standalone and fully annotated
* Treat a scalar role claim as one role; correct step-up docs
* Add v4 version badge to require_roles docs
* Use issuer_url for OAuth issuer identity, not base_url
* Apply ruff format to issuer identity tests
* Align ID-JAG audience docstring with issuer_url
* Make InMemoryOAuthProvider keyword-only like its parent
* Keep ID-JAG audience on base_url, out of scope for issuer identity
* Remove stray scratch script
* Make AuthorizationHandler keyword-only
* Bind ID-JAG audience to the issuer identifier
* Fix double slash in issuer_url well-known log hint
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.
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.
* 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
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.
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
The example README pointed at github.com/PrefectHQ/docket (404); the canonical
repo is chrisguidry/docket. Point the docs' Docket-docs link at the canonical
docket.lol.
* Design doc: stateless session state
* Add stateless session-state primitives: Scope, SessionCodec, scoped state
* Add SessionProvider and Session() annotation for stateless session state
* Rewrite session-state design to final shape (Session object, two patterns, no seal)
* Rework stateless session state to final Session/SessionId design
Remove Scope, SessionCodec/sealing, and scoped ctx.get_state. Add the
Session object (get/set/delete/clear over one dict per (principal,
session_id) key), injected session: Session (keyed by principal, requires
auth), session_id: SessionId argument with auto-filled description, and
SessionProvider contributing create_session/end_session.
* Rename injected marker to UserSession; auto-wire SessionProvider on SessionId
* Document stateless session state as a v4 feature
* Require SessionProvider and make sessions create-then-validate
Remove the implicit SessionProvider auto-wiring; a SessionProvider must now be
registered explicitly. create_session records an owned session and get_session
validates the id, rejecting uncreated or foreign ids.
* Add Session.id (public id for session_id sessions, None for UserSession)
* Fix ty: narrow Tool | None and ToolResult.structured_content in session tests
* Fix session-provider enforcement gap for non-local tools; stop embedding raw principal in UserSession key
* Fix disabled session_id tools blocking listing; reject local tools shadowing SessionProvider lifecycle names
* Decouple SessionId description from lifecycle tool name so it survives namespaced mounts
* Remove SessionProvider enforcement; get_session validation is the guarantee
* Fix stale enforcement/key-format docs; document store-owned session TTL
* Dedup SessionId contract description; tighten context.mdx session-state lead
* Make session store/description resolution work in Docket task workers and for partial tools
* Expose get_session as a standalone task-safe function; drop foreground-only Context.get_session
* Move get_session to dependencies alongside the other request accessors
* Reframe context state docs as Request State; cross-request persistence points to Session State
* Address UserSession injection edge cases from review
- inject a UserSession instance (not bare Session) so isinstance holds
- support session: UserSession | None = None (inject None when unauth)
- detect SessionId params past a partial's positional binding
- Client task support is opt-in via importing fastmcp_tasks (drop the core
auto-load of companion packages); a plain Client never advertises tasks.
- A worker restores the submitting caller's auth token and headers from the
task snapshot into the standard ambient context, so get_access_token() /
get_http_headers() work in a distributed worker with no new core hooks.
- worker_cli validates the loaded extension's resolved backend, not env defaults,
so a constructor-configured Redis worker starts.
- Thread the per-call read timeout through task polling; bound ToolTask.wait by
its deadline; set_elicitation_callback rebuilds internal extensions so a
later-set handler answers in-task input.
- README imports TaskConfig from fastmcp.utilities.tasks.
Co-Authored-By: Claude <noreply@anthropic.com>
Server (servers/tasks.mdx) and client (clients/tasks.mdx) docs rewritten for
the extension model: add_extension(TasksExtension()), the guard pattern for
in-task input (no imperative ctx.elicit()), tools-only, and the modern-protocol
requirement (the inverse of the old SEP-1686 legacy-only note). Mechanical
fixes elsewhere for the same reason: telemetry.mdx's tasks/{operation} method
list (get/update/cancel, not result/list), client.mdx's legacy-only feature
list (tasks moved to modern-only) and extension-composition paragraph
(describes the tasks ClientExtension, not the removed notification binding),
and stale SEP-1686 references in the FastMCP 2 upgrade guide. v4-notes status
lines updated to Shipped (#4602, #4603).
Engine modules (keys, context snapshot, docket lifespan, worker CLI,
client handles) move intact; SEP-1686 wire modules park in _legacy_wire
for adaptation to SEP-2663. Core keeps task=True declaration on tools
only and raises at serve time until the tasks extension is registered.
Co-Authored-By: Claude <noreply@anthropic.com>
* Add M2M client credentials auth providers
Wrap the SDK's client_credentials and private_key_jwt OAuth providers as
FastMCP-idiomatic ClientCredentialsOAuthProvider and PrivateKeyJWTOAuthProvider,
enabling browser-free client authentication via Client(auth=...).
* Fix M2M token cache collision and explicit-scope drop
Namespace the token cache by client_id so distinct clients sharing one store don't overwrite each other's tokens; pin caller-supplied scopes so the token request keeps them; fix CodeQL URL-substring check in tests; drop unused logger.
* Preserve step-up scope union, scope-aware token cache, restore token expiry
Only pin the caller's explicit scopes on initial authorization, leaving the SDK's step-up scope union intact; namespace the token cache by requested scopes as well as client_id; restore persisted absolute expiry on init so an expired stored token is re-fetched.
* Skip expiry restore for non-expiring reloaded tokens
* Distinguish expires_in=0 from omitted when restoring expiry
* Scope step-up flag to the flow via ContextVar; runnable JWT signing example
