fix(mcp): tighten A2A and release verification

.github/workflows/release-please.yml

@@ -360,30 +360,7 @@ jobs:
           MCP_SERVER_VERSION: ${{ steps.mcp-manifest.outputs.version }}
         run: |
           set -euo pipefail
-          encoded_name="$(python3 - <<'PY'
-          import os
-          import urllib.parse
-
-          print(urllib.parse.quote(os.environ["MCP_SERVER_NAME"], safe=""))
-          PY
-          )"
-          curl -fsSL "https://registry.modelcontextprotocol.io/v0.1/servers?search=${encoded_name}" -o /tmp/mcp-registry.json || echo '{"servers":[]}' > /tmp/mcp-registry.json
-          already_published="$(python3 - <<'PY'
-          import json
-          import os
-          from pathlib import Path
-
-          data = json.loads(Path("/tmp/mcp-registry.json").read_text())
-          name = os.environ["MCP_SERVER_NAME"]
-          version = os.environ["MCP_SERVER_VERSION"]
-          exists = any(
-            item.get("server", {}).get("name") == name and
-            item.get("server", {}).get("version") == version
-            for item in data.get("servers", [])
-          )
-          print("true" if exists else "false")
-          PY
-          )"
+          already_published="$(node scripts/mcp-registry-version.mjs --check)"
           echo "already_published=${already_published}" >> "$GITHUB_OUTPUT"
 
       - name: Authenticate to MCP Registry
@@ -398,33 +375,7 @@ jobs:
         env:
           MCP_SERVER_NAME: ${{ steps.mcp-manifest.outputs.name }}
           MCP_SERVER_VERSION: ${{ steps.mcp-manifest.outputs.version }}
-        run: |
-          set -euo pipefail
-          encoded_name="$(python3 - <<'PY'
-          import os
-          import urllib.parse
-
-          print(urllib.parse.quote(os.environ["MCP_SERVER_NAME"], safe=""))
-          PY
-          )"
-          curl -fsSL "https://registry.modelcontextprotocol.io/v0.1/servers?search=${encoded_name}" -o /tmp/mcp-registry.json
-          python3 - <<'PY'
-          import json
-          import os
-          from pathlib import Path
-
-          data = json.loads(Path("/tmp/mcp-registry.json").read_text())
-          name = os.environ["MCP_SERVER_NAME"]
-          version = os.environ["MCP_SERVER_VERSION"]
-
-          for item in data.get("servers", []):
-            server = item.get("server", {})
-            if server.get("name") == name and server.get("version") == version:
-              print(f"Verified {name} {version}")
-              break
-          else:
-            raise SystemExit(f"Registry search did not return {name} {version}")
-          PY
+        run: node scripts/mcp-registry-version.mjs
 
   publish-pypi:
     needs: release-please
@@ -608,30 +559,7 @@ jobs:
           MCP_SERVER_VERSION: ${{ steps.mcp-manifest.outputs.version }}
         run: |
           set -euo pipefail
-          encoded_name="$(python3 - <<'PY'
-          import os
-          import urllib.parse
-
-          print(urllib.parse.quote(os.environ["MCP_SERVER_NAME"], safe=""))
-          PY
-          )"
-          curl -fsSL "https://registry.modelcontextprotocol.io/v0.1/servers?search=${encoded_name}" -o /tmp/mcp-registry.json || echo '{"servers":[]}' > /tmp/mcp-registry.json
-          already_published="$(python3 - <<'PY'
-          import json
-          import os
-          from pathlib import Path
-
-          data = json.loads(Path("/tmp/mcp-registry.json").read_text())
-          name = os.environ["MCP_SERVER_NAME"]
-          version = os.environ["MCP_SERVER_VERSION"]
-          exists = any(
-            item.get("server", {}).get("name") == name and
-            item.get("server", {}).get("version") == version
-            for item in data.get("servers", [])
-          )
-          print("true" if exists else "false")
-          PY
-          )"
+          already_published="$(node scripts/mcp-registry-version.mjs --check)"
           echo "already_published=${already_published}" >> "$GITHUB_OUTPUT"
 
       - name: Authenticate to MCP Registry
@@ -665,33 +593,7 @@ jobs:
         env:
           MCP_SERVER_NAME: ${{ steps.mcp-manifest.outputs.name }}
           MCP_SERVER_VERSION: ${{ steps.mcp-manifest.outputs.version }}
-        run: |
-          set -euo pipefail
-          encoded_name="$(python3 - <<'PY'
-          import os
-          import urllib.parse
-
-          print(urllib.parse.quote(os.environ["MCP_SERVER_NAME"], safe=""))
-          PY
-          )"
-          curl -fsSL "https://registry.modelcontextprotocol.io/v0.1/servers?search=${encoded_name}" -o /tmp/mcp-registry.json
-          python3 - <<'PY'
-          import json
-          import os
-          from pathlib import Path
-
-          data = json.loads(Path("/tmp/mcp-registry.json").read_text())
-          name = os.environ["MCP_SERVER_NAME"]
-          version = os.environ["MCP_SERVER_VERSION"]
-
-          for item in data.get("servers", []):
-            server = item.get("server", {})
-            if server.get("name") == name and server.get("version") == version:
-              print(f"Verified {name} {version}")
-              break
-          else:
-            raise SystemExit(f"Registry search did not return {name} {version}")
-          PY
+        run: node scripts/mcp-registry-version.mjs
 
   publish-rubygems:
     needs: release-please

package.json

@@ -4,7 +4,7 @@
   "private": true,
   "packageManager": "pnpm@10.22.0",
   "scripts": {
-    "build": "pnpm drift:check && pnpm -r --if-present build && pnpm verify:layout && pnpm verify:ts-public-api && pnpm verify:tree-shaking && pnpm test:ts-helpers && pnpm test:ts-ai-sdk && pnpm test:python-release-guardrails && pnpm test:windows-command-shims && pnpm test:chocolatey-asset-tools && pnpm test:chocolatey-workflow-order && pnpm test:snap-workflow && pnpm test:cli-tarball-tools && pnpm check:cli && pnpm check:surface-coverage && pnpm check:live-e2e && pnpm build:go && pnpm build:python && pnpm build:php && pnpm build:ruby && pnpm build:mcp",
+    "build": "pnpm drift:check && pnpm -r --if-present build && pnpm verify:layout && pnpm verify:ts-public-api && pnpm verify:tree-shaking && pnpm test:ts-helpers && pnpm test:ts-ai-sdk && pnpm test:python-release-guardrails && pnpm test:mcp-registry-version && pnpm test:windows-command-shims && pnpm test:chocolatey-asset-tools && pnpm test:chocolatey-workflow-order && pnpm test:snap-workflow && pnpm test:cli-tarball-tools && pnpm check:cli && pnpm check:surface-coverage && pnpm check:live-e2e && pnpm build:go && pnpm build:python && pnpm build:php && pnpm build:ruby && pnpm build:mcp",
     "build:go": "pnpm generate:go && node scripts/check-go.mjs && cd go && go test ./... && go vet ./... && go run github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.3.0 run",
     "build:live-e2e-surfaces": "pnpm drift:check && pnpm -r --if-present build && pnpm build:go && pnpm build:python && pnpm build:php && pnpm build:ruby && pnpm build:mcp",
     "build:mcp": "pnpm generate:mcp && node scripts/check-mcp.mjs",
@@ -42,6 +42,7 @@
     "test:ts-helpers": "node scripts/test-ts-helpers.mjs",
     "test:ts-ai-sdk": "node scripts/test-ts-ai-sdk.mjs",
     "test:python-release-guardrails": "node scripts/test-python-release-guardrails.mjs",
+    "test:mcp-registry-version": "node --test scripts/mcp-registry-version.test.mjs",
     "test:windows-command-shims": "node scripts/test-windows-command-shims.mjs",
     "verify:codegen": "node scripts/verify-normalized-openapi.mjs",
     "verify:layout": "node scripts/verify-layout.mjs",

packages/python/mcp/sendmux_mcp/a2a.py

@@ -28,6 +28,7 @@
     SecurityRequirement,
     SecurityScheme,
     StringList,
+    VersionNotSupportedError,
 )
 from fastmcp.server.auth import AccessToken
 from pydantic import BaseModel, ConfigDict, Field, ValidationError, model_validator
@@ -51,6 +52,8 @@
 OAUTH_TOKEN_URL = "https://app.sendmux.ai/mcp/oauth/token"
 OAUTH_PROTECTED_RESOURCE_METADATA_URL = "https://a2a.sendmux.ai/.well-known/oauth-protected-resource"
 A2A_PATH_PREFIX = "/a2a/v1"
+A2A_PROTOCOL_VERSION = "1.0"
+A2A_HSTS_HEADER = "max-age=63072000; includeSubDomains"
 A2A_RESPONSE_HEADERS = {
     "cache-control",
     "content-type",
@@ -143,6 +146,15 @@ async def verify_token(self, token: str) -> AccessToken | None: ...
 
 class A2AServerCallContextBuilder(DefaultServerCallContextBuilder):
     def build(self, request: Request) -> ServerCallContext:
+        requested_version = request.headers.get("A2A-Version") or "0.3"
+        version_match = re.fullmatch(r"(\d+)\.(\d+)(?:\.[0-9A-Za-z.-]+)?", requested_version)
+        if version_match is None or ".".join(version_match.groups()[:2]) != A2A_PROTOCOL_VERSION:
+            raise VersionNotSupportedError(
+                message=(
+                    f"A2A version '{requested_version}' is not supported by this handler. "
+                    f"Expected version '{A2A_PROTOCOL_VERSION}'."
+                )
+            )
         context = super().build(request)
         access_token = request.scope.get("a2a_access_token")
         if access_token is not None:
@@ -230,7 +242,7 @@ def build_a2a_http_components(
         route for route in rest_routes if isinstance(route, Route) and route.path == f"{A2A_PATH_PREFIX}/message:send"
     )
     routes: list[BaseRoute] = [
-        *create_agent_card_routes(card),
+        *cacheable_agent_card_routes(card),
         Route(
             "/.well-known/oauth-protected-resource",
             endpoint=a2a_protected_resource_metadata,
@@ -241,6 +253,27 @@ def build_a2a_http_components(
     return A2AHttpComponents(routes=routes, request_handler=request_handler, proxy=proxy)
 
 
+def cacheable_agent_card_routes(card: AgentCard) -> list[BaseRoute]:
+    card_route = create_agent_card_routes(card)[0]
+    card_endpoint = card_route.endpoint
+    etag = f'"{card.version}"'
+    cache_headers = {
+        "Cache-Control": "public, max-age=300",
+        "ETag": etag,
+        "Access-Control-Allow-Origin": "*",
+        "Strict-Transport-Security": A2A_HSTS_HEADER,
+    }
+
+    async def endpoint(request: Request) -> Response:
+        if etag in {value.strip() for value in request.headers.get("if-none-match", "").split(",")}:
+            return Response(status_code=304, headers=cache_headers)
+        response = await card_endpoint(request)
+        response.headers.update(cache_headers)
+        return response
+
+    return [Route(card_route.path, endpoint=endpoint, methods=["GET"])]
+
+
 def protected_a2a_route(route: Route, token_verifier: A2ATokenVerifier) -> Route:
     async def endpoint(request: Request) -> Response:
         authorization = request.headers.get("authorization", "")
@@ -251,11 +284,16 @@ async def endpoint(request: Request) -> Response:
                 {"error": "invalid_token"},
                 status_code=401,
                 headers={
-                    "WWW-Authenticate": f'Bearer resource_metadata="{OAUTH_PROTECTED_RESOURCE_METADATA_URL}"'
+                    "Content-Type": "application/a2a+json",
+                    "WWW-Authenticate": f'Bearer resource_metadata="{OAUTH_PROTECTED_RESOURCE_METADATA_URL}"',
+                    "Strict-Transport-Security": A2A_HSTS_HEADER,
                 },
             )
         request.scope["a2a_access_token"] = access_token
-        return await route.endpoint(request)
+        response = await route.endpoint(request)
+        response.headers["Content-Type"] = "application/a2a+json"
+        response.headers["Strict-Transport-Security"] = A2A_HSTS_HEADER
+        return response
 
     return Route(route.path, endpoint=endpoint, methods=["POST"])
 
@@ -269,7 +307,11 @@ async def a2a_protected_resource_metadata(_request: Request) -> JSONResponse:
             "bearer_methods_supported": ["header"],
             "resource_name": "Sendmux A2A",
         },
-        headers={"Cache-Control": "public, max-age=300", "Access-Control-Allow-Origin": "*"},
+        headers={
+            "Cache-Control": "public, max-age=300",
+            "Access-Control-Allow-Origin": "*",
+            "Strict-Transport-Security": A2A_HSTS_HEADER,
+        },
     )
 
 
@@ -347,7 +389,7 @@ def build_a2a_agent_card() -> AgentCard:
             AgentInterface(
                 url=A2A_RESOURCE_URL,
                 protocol_binding="HTTP+JSON",
-                protocol_version="1.0",
+                protocol_version=A2A_PROTOCOL_VERSION,
             )
         ],
         capabilities=AgentCapabilities(

packages/python/mcp/tests/test_a2a_server.py

@@ -2,6 +2,8 @@
 
 import asyncio
 import json
+import re
+from pathlib import Path
 
 import httpx
 from a2a.client import ClientConfig, ClientFactory
@@ -31,9 +33,13 @@
 
 def test_agent_card_advertises_a2a_1_0_http_json_and_oauth() -> None:
     card = agent_card_to_dict(build_a2a_agent_card())
+    pyproject = (Path(__file__).parents[1] / "pyproject.toml").read_text()
+    project = pyproject.split("[project]", maxsplit=1)[1].split("\n[", maxsplit=1)[0]
+    package_version = re.search(r'^version = "([^"]+)"$', project, re.MULTILINE)
 
     assert card["name"] == "Sendmux A2A"
-    assert card["version"] == "1.5.1"
+    assert package_version is not None
+    assert card["version"] == package_version.group(1)
     assert card["description"]
     assert card["supportedInterfaces"] == [
         {
@@ -182,18 +188,48 @@ async def proxy_handler(request: httpx.Request) -> httpx.Response:
         ) as http_client:
             card_response = await http_client.get("/.well-known/agent-card.json")
             assert card_response.status_code == 200
+            assert "max-age=" in card_response.headers["cache-control"]
+            assert card_response.headers["etag"]
+            assert card_response.headers["strict-transport-security"].startswith("max-age=")
+
+            cached_card_response = await http_client.get(
+                "/.well-known/agent-card.json",
+                headers={"If-None-Match": card_response.headers["etag"]},
+            )
+            assert cached_card_response.status_code == 304
+            assert cached_card_response.content == b""
 
             resource_response = await http_client.get("/.well-known/oauth-protected-resource")
             assert resource_response.status_code == 200
             assert resource_response.json()["resource"] == A2A_RESOURCE_URL
+            assert resource_response.headers["strict-transport-security"].startswith("max-age=")
 
             missing_auth = await http_client.post(
                 "/a2a/v1/message:send",
                 headers={"Authorization": ""},
                 json={},
             )
             assert missing_auth.status_code == 401
+            assert missing_auth.headers["content-type"] == "application/a2a+json"
             assert missing_auth.headers["www-authenticate"].startswith("Bearer resource_metadata=")
+            assert missing_auth.headers["strict-transport-security"].startswith("max-age=")
+
+            unsupported_version = await http_client.post(
+                "/a2a/v1/message:send",
+                content=b"{}",
+                headers={"A2A-Version": "0.3", "Content-Type": "application/a2a+json"},
+            )
+            assert unsupported_version.status_code == 400
+            assert unsupported_version.headers["content-type"] == "application/a2a+json"
+            assert unsupported_version.json()["error"]["details"][0]["reason"] == "VERSION_NOT_SUPPORTED"
+
+            unsupported_minor_version = await http_client.post(
+                "/a2a/v1/message:send",
+                content=b"{}",
+                headers={"A2A-Version": "1.1", "Content-Type": "application/a2a+json"},
+            )
+            assert unsupported_minor_version.status_code == 400
+            assert unsupported_minor_version.json()["error"]["details"][0]["reason"] == "VERSION_NOT_SUPPORTED"
 
             assert (await http_client.post("/a2a/v1/message:stream", json={})).status_code == 404
             assert (await http_client.get("/a2a/v1/tasks/task_123")).status_code == 404