[HarshPopat23]

Summary

Add focused conformance tests for MCP metadata, parameter headers and continuations across the four supported protocol revisions.

This PR changes only test coverage and its CMake registration. Production validation behavior, public APIs and benchmarks remain unchanged.

Changes

Version-specific conformance matrix

Exercise explicit expectations across:

• 2025-03-26
• 2025-06-18
• 2025-11-25
• 2026-07-28

Verify request-metadata requirements, continuation availability and rejection of parameter-header validation under unsupported revisions.

Deterministic property tests

• Round-trip all 95 printable ASCII bytes through parameter-header generation and validation.
• Reject a changed argument value for every generated ASCII fixture.
• Verify Unicode header values, including surrounding whitespace.
• Check all 25 combinations of five continuation tokens, covering empty strings, casing, whitespace and Unicode.
• Reject unsolicited continuation state tokens.

These tests use explicit expected outcomes rather than deriving expectations from the feature helpers under test.

Root-identifier receive policy

Separate rejection of non-file identifiers from characterization of the current prefix-based receive behavior.

The tests explicitly identify acceptance of file://bad space and file:// as current behavior—not evidence that these are valid URIs.

Maintainer guidance requested

The [2026-07-28 schema](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/main/schema/2026-07-28/schema.ts) requires root identifiers to start with file:// and annotates the field with @format uri.

Should continuation validation additionally enforce complete URI syntax, or retain the existing prefix-based receive policy?

No stricter URI checks are introduced pending agreement.

Verification

• GCC 13.3, Linux, Release build passed.
• Complete MCP suite: 1,429 passed, zero failed, including nine new tests.
• Repository clang-format and clang-tidy checks passed.
• Runnable acceptance checks were reverified.
• Published source matches the locally verified files.

Scope and limitations

These are bounded, deterministic property tests—not exhaustive protocol certification or fuzz testing.

This PR does not implement resource authorization, filesystem containment, SSRF protection or continuation replay protection. It preserves the existing application boundaries.

No internal Markdown notes, additional dependencies or performance claims are included.

[augmentcode]

🤖 Augment PR Summary

Summary: Adds focused MCP conformance and receive-policy coverage.

• Registers nine new tests in the existing MCP CMake target.
• Covers all four supported protocol revisions.
• Checks request-metadata version acceptance and rejection.
• Verifies continuation support and legacy parameter-header rejection.
• Round-trips all 95 printable ASCII bytes with changed-body negative controls.
• Exercises Unicode header values, including surrounding whitespace.
• Checks all 25 state-token combinations and rejects unsolicited state.
• Separates non-file root rejection from current prefix-based acceptance.

Scope: Preserves production behavior and public APIs; stricter URI validation remains undecided.

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[augmentcode]

Review completed. No suggestions at this time.

Comment augment review to trigger a new review at any time.

[jviotti]

Please use the existing test files to add tests where relevant. If you think about it, all tests we have are by definition "conformance" as that's the point!

[jviotti]

Also try to avoid using loops in tests. This should really be 3 different tests. In general, a good unit test should be sequential and direct.

[jviotti]

Much better! But can we prettify all JSON documents on all the new tests? Otherwise these big lines are very hard to read. There is no reason why they have to be a single stringified line?