ci: add discovery conformance coverage

Author: DaleSeo

.github/workflows/conformance.yml

@@ -34,7 +34,7 @@ jobs:
       - name: Build conformance binaries
         run: cargo build -p mcp-conformance
 
-      - name: Start conformance server
+      - name: Start 2025-11-25 server
         run: |
           PORT=8001 ./target/debug/conformance-server &
           echo $! > server.pid
@@ -47,7 +47,7 @@ jobs:
           echo "conformance server did not become ready" >&2
           exit 1
 
-      - name: Run server conformance suite
+      - name: Run 2025-11-25 server suite
         run: |
           npx -y "@modelcontextprotocol/conformance@${CONFORMANCE_VERSION}" server \
             --url http://127.0.0.1:8001/mcp \
@@ -56,7 +56,7 @@ jobs:
 
       # These pass today but are excluded from the default "active" suite;
       # run them explicitly so regressions are still caught.
-      - name: Run pending scenarios
+      - name: Run 2025-11-25 pending scenarios
         run: |
           for scenario in json-schema-2020-12 server-sse-polling; do
             npx -y "@modelcontextprotocol/conformance@${CONFORMANCE_VERSION}" server \
@@ -65,7 +65,7 @@ jobs:
               -o conformance-results
           done
 
-      - name: Start draft conformance server
+      - name: Start draft server
         run: |
           STATELESS=1 PORT=8002 ./target/debug/conformance-server &
           echo $! > draft-server.pid
@@ -78,22 +78,87 @@ jobs:
           echo "draft conformance server did not become ready" >&2
           exit 1
 
-      - name: Run draft SEP scenarios
+      # The upstream server-stateless scenario also covers client capability
+      # enforcement and subscriptions/listen, which land in follow-up PRs.
+      # Exercise the discovery/version-negotiation contract independently until
+      # the full draft suite is enabled by #985.
+      - name: Run SEP-2575 discovery contract
         run: |
-          for scenario in sep-2164-resource-not-found caching http-header-validation; do
-            npx -y "@modelcontextprotocol/conformance@${DRAFT_CONFORMANCE_VERSION}" server \
-              --url http://127.0.0.1:8002/mcp \
-              --scenario "$scenario" \
-              --spec-version draft \
-              -o conformance-results
-          done
-
-      # SEP-2322 MRTR scenarios (spec 2026-07-28). They speak the stateless
-      # lifecycle (bare JSON-RPC POSTs, no initialize handshake), so they run
-      # against the stateless draft server.
-      - name: Run SEP-2322 MRTR scenarios
+          endpoint=http://127.0.0.1:8002/mcp
+          common_headers=(
+            -H "Content-Type: application/json"
+            -H "Accept: application/json, text/event-stream"
+            -H "Mcp-Method: server/discover"
+          )
+
+          discover_response="$(
+            curl --fail-with-body --silent --show-error \
+              "${common_headers[@]}" \
+              -H "MCP-Protocol-Version: 2026-07-28" \
+              --data '{
+                "jsonrpc": "2.0",
+                "id": "discover",
+                "method": "server/discover",
+                "params": {
+                  "_meta": {
+                    "io.modelcontextprotocol/protocolVersion": "2026-07-28",
+                    "io.modelcontextprotocol/clientInfo": {
+                      "name": "conformance-workflow",
+                      "version": "1.0.0"
+                    },
+                    "io.modelcontextprotocol/clientCapabilities": {}
+                  }
+                }
+              }' \
+              "$endpoint"
+          )"
+          jq -e '
+            .result.resultType == "complete" and
+            (.result.supportedVersions | index("2026-07-28") != null) and
+            (.result.capabilities | type == "object") and
+            (.result.serverInfo.name | type == "string") and
+            .result.ttlMs == 0 and
+            .result.cacheScope == "private"
+          ' <<<"$discover_response"
+
+          status="$(
+            curl --silent --show-error \
+              --output /tmp/unsupported-version.json \
+              --write-out "%{http_code}" \
+              "${common_headers[@]}" \
+              -H "MCP-Protocol-Version: 2099-01-01" \
+              --data '{
+                "jsonrpc": "2.0",
+                "id": "unsupported",
+                "method": "server/discover",
+                "params": {
+                  "_meta": {
+                    "io.modelcontextprotocol/protocolVersion": "2099-01-01",
+                    "io.modelcontextprotocol/clientInfo": {
+                      "name": "conformance-workflow",
+                      "version": "1.0.0"
+                    },
+                    "io.modelcontextprotocol/clientCapabilities": {}
+                  }
+                }
+              }' \
+              "$endpoint"
+          )"
+          test "$status" = "400"
+          jq -e '
+            .id == "unsupported" and
+            .error.code == -32022 and
+            .error.data.requested == "2099-01-01" and
+            (.error.data.supported | index("2026-07-28") != null)
+          ' /tmp/unsupported-version.json
+
+      # Keep this explicit list until the full draft suite is enabled by #985.
+      - name: Run supported draft server scenarios
         run: |
           for scenario in \
+            sep-2164-resource-not-found \
+            caching \
+            http-header-validation \
             input-required-result-basic-elicitation \
             input-required-result-basic-sampling \
             input-required-result-basic-list-roots \
@@ -112,17 +177,15 @@ jobs:
             npx -y "@modelcontextprotocol/conformance@${DRAFT_CONFORMANCE_VERSION}" server \
               --url http://127.0.0.1:8002/mcp \
               --scenario "$scenario" \
+              --spec-version draft \
               -o conformance-results
           done
 
-      - name: Stop draft conformance server
-        if: always()
-        run: kill "$(cat draft-server.pid)" 2>/dev/null || true
-
-
-      - name: Stop conformance server
+      - name: Stop conformance servers
         if: always()
-        run: kill "$(cat server.pid)" 2>/dev/null || true
+        run: |
+          kill "$(cat draft-server.pid)" 2>/dev/null || true
+          kill "$(cat server.pid)" 2>/dev/null || true
 
       - name: Upload results
         if: always()
@@ -146,7 +209,7 @@ jobs:
       - name: Build conformance binaries
         run: cargo build -p mcp-conformance
 
-      - name: Run full client conformance suite
+      - name: Run 2025-11-25 client suite
         run: |
           npx -y "@modelcontextprotocol/conformance@${CONFORMANCE_VERSION}" client \
             --command "$(pwd)/target/debug/conformance-client" \
@@ -155,7 +218,7 @@ jobs:
             -o conformance-client-results/full
 
       # SEP-2322 MRTR client scenario (spec 2026-07-28).
-      - name: Run SEP-2322 MRTR client scenario
+      - name: Run draft SEP-2322 client scenario
         run: |
           npx -y "@modelcontextprotocol/conformance@${DRAFT_CONFORMANCE_VERSION}" client \
             --command "$(pwd)/target/debug/conformance-client" \