fix(server): return stdio parse errors

.github/ISSUE_TEMPLATE/v2-feedback 2.yaml

@@ -0,0 +1,59 @@
+name: v2 feedback
+description: Bugs, API friction, or docs gaps in v2 of the SDK
+title: "[v2] "
+labels: ["v2-alpha"]
+
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for trying v2. Anything that broke, surprised you, or slowed you down is useful — API feedback is explicitly welcome while v2 is in pre-release.
+
+        Docs: https://py.sdk.modelcontextprotocol.io/v2/ · Migration from v1: https://py.sdk.modelcontextprotocol.io/v2/migration/
+
+  - type: textarea
+    id: what
+    attributes:
+      label: What happened?
+      description: What did you do, and what went wrong (or felt wrong)? Paste error output verbatim if there is any.
+    validations:
+      required: true
+
+  - type: textarea
+    id: expected
+    attributes:
+      label: What did you expect?
+    validations:
+      required: false
+
+  - type: textarea
+    id: repro
+    attributes:
+      label: Code to reproduce
+      description: The smallest snippet or repository that shows it. For docs feedback, link the page instead.
+      render: Python
+    validations:
+      required: false
+
+  - type: input
+    id: version
+    attributes:
+      label: SDK version
+      description: The published version (`pip show mcp`) or commit.
+    validations:
+      required: false
+
+  - type: dropdown
+    id: area
+    attributes:
+      label: Area
+      options:
+        - Server
+        - Client
+        - Transports
+        - Auth
+        - Documentation
+        - Migration
+        - Other
+    validations:
+      required: false

.github/actions/conformance/run-client 2.sh

@@ -0,0 +1,104 @@
+#!/bin/bash
+# Run a client conformance suite, re-verifying unexpected failures solo.
+# Concurrent suite runs on a 2-vCPU runner can push scenarios with real-time
+# waits past tolerance; solo, a real failure fails again while a contention
+# artifact passes. Failures that only reproduce under concurrency are excused.
+set -uo pipefail
+
+: "${CONFORMANCE_PKG:?set CONFORMANCE_PKG (pinned in .github/workflows/conformance.yml)}"
+# One attempt: a solo failure on the quiet runner disproves the contention
+# hypothesis; a second try would be the blind retry this script avoids.
+SOLO_ATTEMPTS="${CONFORMANCE_SOLO_ATTEMPTS:-1}"
+
+# Relative args resolve from the repo root; same contract as run-server.sh.
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+cd "$SCRIPT_DIR/../../.." || exit 1
+
+log="$(mktemp)"
+trap 'rm -f "$log"' EXIT
+
+npx --yes "$CONFORMANCE_PKG" client "$@" 2>&1 | tee "$log"
+rc=${PIPESTATUS[0]}
+if [ "$rc" -eq 0 ]; then
+    exit 0
+fi
+
+plain="$(sed 's/\x1b\[[0-9;]*m//g' "$log")"
+
+# If the harness's summary wording changes, the list comes up empty and the
+# original exit code passes through - never a false green.
+mapfile -t scenarios < <(
+    printf '%s\n' "$plain" |
+        sed -n '/^Unexpected failures (not in baseline):$/,/^$/p' |
+        sed -n 's/^  ✗ //p'
+)
+if [ "${#scenarios[@]}" -eq 0 ]; then
+    exit "$rc"
+fi
+for scenario in "${scenarios[@]}"; do
+    if ! [[ "$scenario" =~ ^[A-Za-z0-9/_-]+$ ]]; then
+        echo "Extracted unexpected-failure name '${scenario}' does not look like a scenario name; passing the suite failure through." >&2
+        exit "$rc"
+    fi
+done
+
+# A stale baseline entry is a configuration error a solo rerun cannot excuse.
+# Here-string, not a pipe: grep -q quitting early would SIGPIPE printf and,
+# under pipefail, skip this guard exactly when the pattern is present.
+if grep -q '^Stale baseline entries' <<<"$plain"; then
+    echo "Suite also reported stale baseline entries; not retrying." >&2
+    exit "$rc"
+fi
+
+# Drop the suite-only flags: --scenario replaces --suite, and solo runs are
+# judged directly rather than against the baseline.
+rerun_args=()
+output_dir=""
+skip_next=0
+expect_output_dir=0
+for arg in "$@"; do
+    if [ "$skip_next" -eq 1 ]; then
+        if [ "$expect_output_dir" -eq 1 ]; then
+            output_dir="$arg"
+        fi
+        skip_next=0
+        expect_output_dir=0
+        continue
+    fi
+    case "$arg" in
+    --output-dir)
+        skip_next=1
+        expect_output_dir=1
+        ;;
+    --suite | --expected-failures) skip_next=1 ;;
+    --output-dir=*) output_dir="${arg#--output-dir=}" ;;
+    --suite=* | --expected-failures=*) ;;
+    *) rerun_args+=("$arg") ;;
+    esac
+done
+if [ -n "$output_dir" ]; then
+    rerun_args+=(--output-dir "${output_dir}-solo")
+fi
+
+for scenario in "${scenarios[@]}"; do
+    passed=0
+    for attempt in $(seq 1 "$SOLO_ATTEMPTS"); do
+        echo ""
+        echo "Re-running '${scenario}' solo (attempt ${attempt}/${SOLO_ATTEMPTS})..."
+        if npx --yes "$CONFORMANCE_PKG" client --scenario "$scenario" "${rerun_args[@]}"; then
+            passed=1
+            break
+        fi
+    done
+    if [ "$passed" -ne 1 ]; then
+        echo "'${scenario}' still fails when run alone: real failure, not suite contention." >&2
+        exit 1
+    fi
+done
+
+if [ -n "$output_dir" ]; then
+    mkdir -p "$output_dir"
+    printf '%s\n' "${scenarios[@]}" > "$output_dir/FLAKE_RESCUED"
+fi
+echo "All ${#scenarios[@]} unexpected failure(s) passed when re-run solo; the suite failures were parallel-run contention."
+exit 0