feat(core): Support stable MCP SDK v2 - #22883
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Co-Authored-By: OpenAI Codex <codex@openai.com>
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July 30, 2026 17:23
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Co-Authored-By: OpenAI Codex <codex@openai.com>
Co-Authored-By: OpenAI Codex <codex@openai.com>
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Adds support and end-to-end coverage for the stable split MCP SDK v2 packages. MCP server spans now read protocol and client identity from the 2026-07-28 per-request envelope and server identity from result metadata, while preserving the existing initialize-based extraction for legacy protocol sessions.
The Cloudflare MCP fixture now follows the Agents 0.20.1 stateless factory API and verifies both a modern 2026-07-28 tool call and a claimless legacy-compatible tool call. The Node fixture moves from the v2 alpha to exact stable packages and continues exercising the legacy initialize/session protocol; the separate McpAgent fixture remains unchanged for sessionful v1 coverage.
Root cause
MCP 2026-07-28 does not perform the initialize exchange that previously supplied protocol and implementation metadata, so v2 tool spans were created but omitted mcp.protocol.version, mcp.client., and mcp.server. attributes.
Fixes #22878