[Shreyavemana]

Summary

Addresses (#78), which updates the requirements for (#24) to align the SDK's wire behavior with the MCP 2026 protocol.

Changes

• Ping behavior: Return -32601 (METHOD_NOT_FOUND) for ping requests in auto and modern protocol modes while preserving legacy behavior.
• Missing client capability error: Added MISSING_REQUIRED_CLIENT_CAPABILITY with error code -32021.
• Task capability validation: Return -32021 when a tool is invoked as a task but task support is unavailable for the active protocol version.
• Discovery metadata: Added io.modelcontextprotocol/serverInfo to the _meta field of server/discover responses.
• Result type: Ensure discovery responses include resultType: "complete".
• HTTP-level tests: Added tests/test_mcp26_wire.py to cover the updated wire behavior.

Tests

Added:

• tests/test_mcp26_wire.py
  • Verifies protocol-specific ping behavior.
  • Covers the missing client capability error.
  • Checks discovery metadata and MCP 2026 response behavior.

Verification

• tests/test_mcp26_wire.py — 11 passed .
• tests/test_transport_http.py and tests/test_lifecycle_http.py — 11 passed in an run.

Note: Re-run the tests after rebasing onto upstream/develop to confirm the final results.

Related Issues

• [Issue #24 — MCP 2026 wire alignment]([mcp-2026] Align 2026 wire: drop ping, add -32021, discover _meta, MUST headers #24)