test(client): cover delegated MCP thread ids in signed relay URLs

[Mnigos]

Context

#15813 (#15813) was closed in favor of #17599 (#17599), with the note: "If there's test coverage here that #17599 doesn't have, a small follow-up PR adding it is welcome." Since then #17602 (#17602) builds the signed URL from the HttpApi contract. That covers most of what #15813 tested. One thread id shape is still untested.

Threads that OAuth MCP clients delegate get ids like thread:mcp:client%3A<session>:<request>:0, because the server URI-encodes the client:<session> namespace into the id. The id itself contains a %. The current test only uses mcp:<uuid> and checks that the path contains /mcp%3A. Nothing checks that a % in the id goes out as %25, so the server decodes it back to the same id, or that the proof signs that URL.

Change

• The MCP thread id test in environmentHttpAuth.test.ts now runs each thread loader (snapshot, bounded snapshot, history) for both id shapes: mcp:<uuid> and a delegated thread:mcp:client%3A… id.
• It checks the exact request path (…/threads/thread%3Amcp%3Aclient%253Asession-1%3Arequest-1%3A0/bounded and so on) instead of a substring, and still checks that the proof signs the URL that was sent.

Verification

Check	Result
vp test run src/state/environmentHttpAuth.test.ts (client-runtime)	41 passed (3 to 6 MCP thread cases)
vp run typecheck (client-runtime)	passes
vp fmt --check / vp lint on the test file	clean

Test-only change, no UI, so no screenshots.

Implemented with Claude Opus 5.5, coordinated by Claude Fable 5.1 in Claude Code.

[macroscopeapp]

Approvability

Verdict: Approved at 4489991

Macroscope's review found this PR approvable — This is a narrowly scoped, test-only coverage expansion confined to an ignored path, with no production behavior, product-default, or static-analysis configuration changes. Its impact is limited to validating delegated MCP thread ID encoding and signed URL requests in the test harness.

Notes:

• Diff unchanged. Approvability was decided on eligibility alone.

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[coderabbitai]

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📥 Commits

Reviewing files that changed from the base of the PR and between c77a7b7 and 4489991.

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📒 Files selected for processing (1)

• packages/client-runtime/src/state/environmentHttpAuth.test.ts

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📝 Walkthrough

Walkthrough

The HTTP auth test now checks URL encoding for two thread ID shapes across snapshot, bounded snapshot, and history requests. It also verifies that each DPoP proof signs the URL sent by its request.

Changes

Thread URL encoding tests

Layer / File(s)	Summary
Thread request URL assertions packages/client-runtime/src/state/environmentHttpAuth.test.ts	The test runs snapshot, bounded snapshot, and history loaders with an MCP thread ID and a delegated thread ID. It checks each expected pathname and confirms that the DPoP proof URL matches the sent URL.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Other

Suggested reviewers: juliusmarminge

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Merge Risk: ⚪ Minimal · up to 44899

The added coverage does not change runtime behavior, and no issue requiring a fix before merge was identified.

Pre-merge checks | 3 | 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check		The description explains the problem, change, and verification results. It does not provide the required Scope and approval section or clearly document explicit maintainer approval or the applicable s…	Add a Scope and approval section. Link the relevant issue or discussion, include the explicit maintainer approval comment, or explain why this focused test-only change qualifies as an obvious bug fix without prior approval.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check		The title clearly identifies the test change and the delegated MCP thread ID behavior it covers.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

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Full details: Description check

Explanation

The description explains the problem, change, and verification results. It does not provide the required Scope and approval section or clearly document explicit maintainer approval or the applicable small-fix exemption.

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Dismissing prior approval to re-evaluate 4489991