DRAFT: Rename telemetry span attributes to OTEL MCP semantic conventions

[ChrisJBurns]

Summary

• Renames existing span attributes to align with OpenTelemetry HTTP and MCP semantic conventions
• Adds dual emission: new names are always emitted, old names conditionally emitted when UseLegacyAttributes=true (the default)
• Adds mapTransport helper to convert MCP transport types to OTEL network.transport values
• Updates span naming: mcp.tools/call → tools/call github_search (method + resource target)

Key attribute renames:

Old	New
http.method	http.request.method
mcp.method	mcp.method.name
mcp.request.id	jsonrpc.request.id
mcp.tool.name	gen_ai.tool.name
mcp.transport	network.transport

See docs/telemetry-migration.md for the full mapping and migration guide.

Stacked on #3729 (adds the UseLegacyAttributes flag).

Test plan

• Unit tests for dual emission (HTTP, MCP, method-specific, finalizeSpan attributes)
• Unit tests for mapTransport helper
• Unit tests for updated span naming
• Integration test with UseLegacyAttributes=true verifies both old and new names present
• Integration test with UseLegacyAttributes=false verifies only new names present
• task lint passes
• task test passes

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 95.69892% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 66.40%. Comparing base (cf2c338) to head (2aa273b).

Files with missing lines	Patch %	Lines
pkg/telemetry/middleware.go	95.69%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3734      +/-   ##
==========================================
+ Coverage   66.31%   66.40%   +0.09%     
==========================================
  Files         427      427              
  Lines       41800    41860      +60     
==========================================
+ Hits        27718    27796      +78     
+ Misses      11971    11953      -18     
  Partials     2111     2111              

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[ChrisJBurns]

Superseded by #3747 and #3748 — split into two smaller, more reviewable PRs:

• Gate legacy span attributes behind UseLegacyAttributes flag #3747: Gate legacy attributes behind UseLegacyAttributes flag (structural no-op)
• Rename span attributes to MCP OTEL semantic conventions #3748: Rename span attributes to MCP OTEL semantic conventions (adds new names)