modelcontextprotocol/python-sdk
Watch
1
0
Fork
You've already forked python-sdk
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Add a client extension API (#3034)

Browse source
This commit is contained in:
Max 2026-06-30 21:31:02 +01:00 • committed by GitHub
commit 4df609119f
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
1 changed files with 3410 additions and 180 deletions
Download patch file Download diff file Expand all files Collapse all files

76
tests/interaction/_requirements.py
View file

@ -2384,6 +2384,69 @@ REQUIREMENTS: dict[str, Requirement] = {
),
),
# ═══════════════════════════════════════════════════════════════════════════
# Extensions (SEP-2133): client-side result claims and the capability ad
# ═══════════════════════════════════════════════════════════════════════════
"extensions:client:claimed-result-resolved": Requirement(
source=f"{SPEC_2026_BASE_URL}/basic#resulttype",
behavior=(
"A tools/call answered with an extension-claimed resultType is finished by the owning "
"ClientExtension's claim resolver, and Client.call_tool returns the resolver's ordinary "
"CallToolResult. The resolver may send follow-up requests through the session it is handed."
),
added_in="2026-07-28",
),
"extensions:client:claimed-result-undeclared-invalid": Requirement(
source=f"{SPEC_2026_BASE_URL}/basic#resulttype",
behavior=(
"A resultType unrecognized by the client is invalid: a claimed shape delivered to a client that "
"did not construct the owning extension fails result validation (the supported set is core plus "
"declared claims, never more)."
),
added_in="2026-07-28",
note=(
"Known leniency: the monolith result surface still accepts an unknown tag when the payload "
"also parses as a complete core result (open result_type, extras ignored). Rejecting tags "
"outside core plus active claims is a tracked follow-up ruling."
),
),
"extensions:client:capability-ad:gates-server-behaviour": Requirement(
source=f"{SPEC_2026_BASE_URL}/basic#resulttype",
behavior=(
"The per-request _meta capability ad carries each declared extension's identifier and settings, "
"and is what entitles the server to substitute that extension's claimed shapes: a server "
"extension gating on the ad sees the declared settings, and refuses a non-declaring client with "
"-32021 (missing required client capability)."
),
added_in="2026-07-28",
),
"extensions:client:capability-ad:legacy-omits-claimed": Requirement(
source=f"{SPEC_2026_BASE_URL}/basic#resulttype",
behavior=(
"On a legacy connection no claim can activate, and the initialize capability ad omits "
"claim-bearing identifiers in the same breath (claim-less identifiers still advertise), so the "
"client never advertises an extension whose claimed shapes it would reject."
),
removed_in="2026-07-28",
note=(
"The legacy-era half of the ad/claims coupling: only a handshake connection can exhibit it, so "
"the version window ends where the modern era begins."
),
arm_exclusions=(ArmExclusion(reason="requires-session", transport="streamable-http-stateless"),),
),
"extensions:client:notification-binding-delivery": Requirement(
source=f"{SPEC_2026_BASE_URL}/basic#resulttype",
behavior=(
"A vendor server notification bound by a ClientExtension's NotificationBinding is validated "
"against the binding's params type and delivered to its handler serially, in dispatch order."
),
added_in="2026-07-28",
deferred=(
"Covered at session tier by tests/client/test_session_notification_bindings.py: no public "
"server-side surface emits vendor-method notifications (ServerNotification is a closed union), "
"and HTTP-modern arrival additionally needs the subscriptions/listen client runtime."
),
),
# ═══════════════════════════════════════════════════════════════════════════
# Transports (in-suite coverage)
# ═══════════════════════════════════════════════════════════════════════════
"transport:streamable-http:stateful": Requirement(
@ -3341,6 +3404,19 @@ REQUIREMENTS: dict[str, Requirement] = {
transports=("streamable-http",),
note="Only observable over streamable HTTP: headers are derived from the cached tool schema at the seam.",
),
"client-transport:http:vendor-name-param-header": Requirement(
source="sdk",
behavior=(
"A vendor request type declaring name_param mirrors that wire-params key into the Mcp-Name "
"header of its outgoing HTTP request, with no client-side registration of the method."
),
added_in="2026-07-28",
transports=("streamable-http",),
note=(
"SDK mechanism honouring the per-extension Mcp-Name requirements (e.g. SEP-2663 mandates the "
"header for tasks/*); only observable over streamable HTTP, where headers exist."
),
),
"client-transport:http:stateless-ignores-session-id": Requirement(
source=f"{SPEC_2026_BASE_URL}/basic/transports#stateless-request-headers",
behavior=(