2026-07-28 Spec Compliance

[mikekistler]

2026-07-28 Spec Compliance

Track C# SDK compliance with all SEPs scoped to the 2026-07-28 MCP spec release.

SEPs

Final

• SEP-1865: MCP Apps - Interactive User Interfaces for MCP
  • SEP-1865: MCP Apps - Interactive User Interfaces for MCP #1431
• SEP-2133: Extensions framework for MCP
  • completed in Add Extensions support to ClientCapabilities and ServerCapabilities #1317
• SEP-2164: Standardize resource not found error code (-32602)
  • SEP-2164: Standardize resource not found error code (-32602) #1540
• SEP-2243: HTTP Standardization
  • SEP-2243: HTTP Standardization #1541
• SEP-2260: Require Server requests to be associated with a Client request
  • SEP-2260: Require Server requests to be associated with a Client request #1589
• SEP-2567: Sessionless MCP via Explicit State Handles
  • SEP-2567: Sessionless MCP via Explicit State Handles #1548
• SEP-2577: Deprecate Roots, Sampling, and Logging
  • SEP-2577: Deprecate Roots, Sampling, and Logging #1588
• SEP-2663: Tasks Extension
  • SEP-2663: Tasks Extension #1573

Accepted

• SEP-837: Update authorization spec to clarify client type requirements
  • SEP-837: Update authorization spec to clarify client type requirements #1545
• SEP-2106: Tools inputSchema & outputSchema Conform to JSON Schema 2020-12
  • SEP-2106: Tools inputSchema/outputSchema conform to JSON Schema 2020-12 #1550
• SEP-2322: Multi Round-Trip Requests
  • SEP-2322: Multi Round-Trip Requests #1546
• SEP-2350: Clarify client-side scope accumulation in step-up authorization
  • SEP-2350: Clarify client-side scope accumulation in step-up authorization #1547
• SEP-2468: Recommend Issuer (iss) Parameter in MCP Auth Responses
  • SEP-2468: Recommend Issuer (iss) Parameter in MCP Auth Responses #1571
• SEP-2549: TTL for List Results
  • SEP-2549: TTL for List Results #1572
• SEP-2575: Make MCP Stateless
  • SEP-2575: Make MCP Stateless #1549

Not Applicable / No SDK Impact

SEPs ratified/accepted for this release that require no C# SDK code change (governance/process or already-compliant). Marked complete.

• SEP-414: Document OpenTelemetry Trace Context Propagation Conventions
  • no SDK changes needed (already compliant)
• SEP-1730: SDK tiers definition
  • Governance/process — defines tier requirements for SDKs, no code change
• SEP-2207: OIDC-flavored refresh token guidance
  • No SDK support required
• SEP-2351: Explicitly specify RFC 8414 well-known URI suffix for MCP
  • No SDK support needed — clarification only, existing discovery logic already compliant
• SEP-2352: Clarify authorization server binding and migration
  • No SDK support needed — per-instance architecture already maintains separate state per AS
• SEP-2484: Require Conformance Tests for Standards Track SEPs to Reach Final Status
  • Process — requires conformance tests in a separate repo, not SDK code
• SEP-2596: Specification Feature Lifecycle and Deprecation Policy
  • Process — defines lifecycle mechanics (Active→Deprecated→Removed) for spec features

Dropped

• SEP-2145: Standardize tools/call failure reporting
  • SEP-2145: Standardize tools/call failure reporting #1551
• SEP-2200: Clarify tool result content visibility
  • SEP-2200: Clarify tool result content visibility #1552
• SEP-2356: File input support for tools and elicitation