fix(relay): accept delegated thread IDs in activity routes

[juliusmarminge]

Delegated thread IDs can exceed the HTTP router's default 100-character parameter limit, causing valid signed activity updates to miss the route. Raise the relay limit to 512 characters, matching the environment server, and widen both activity and delivery-attempt thread ID columns with a forward migration.

The route regression exercises both ordinary and escaped long IDs through authentication, signature verification, and publication. The 512-character boundary is covered. Applying the full migration history in PostgreSQL/PGlite preserves old rows, accepts 512 characters in both tables, and rejects 513. All 14 API tests, relay typecheck, and targeted lint pass. No visual UI change. The production deployment workflow runs after merging.

Model: GPT-6. Harness: Codex.

Summary by CodeRabbit

• Bug Fixes
  • Fixed relay HTTP routing for delegated thread IDs that are percent-encoded or up to 512 characters long.
  • Ensured these requests authenticate successfully and preserve the original thread ID and environment metadata when publishing activity.
  • Expanded supported thread ID storage capacity to prevent failures when processing longer delegated thread IDs.

[macroscopeapp]

Approvability

Verdict: Approved at 7e8e19c

Macroscope's review found this PR approvable — This is a focused relay bug fix that raises the route and storage limits for delegated thread IDs while preserving existing shorter-ID behavior. The migration is backward-compatible, and targeted tests cover delegated and maximum-length IDs.

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[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.5 KiB	13.5 KiB	+2 B (+0.0%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.1 KiB	7.0 KiB	−3 B (−0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.5 KiB	6.5 KiB	+5 B (+0.1%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	56.2 KiB	56.3 KiB	+44 B (+0.1%)	66.4 KiB	✅
Codex	Live turn messages	9	10	+1 (+11.1%)	21	✅
Claude	Total thread wire	13.5 KiB	13.5 KiB	+20 B (+0.1%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.1 KiB	7.1 KiB	+3 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.4 KiB	6.5 KiB	+17 B (+0.3%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	57.0 KiB	57.0 KiB	0 B (0.0%)	66.4 KiB	✅
Claude	Live turn messages	9	9	0 (0.0%)	21	✅

Baseline: ccad9f6 · PR result: 7e8e19c · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 114.0 KiB
• Claude decoded thread snapshot: 114.7 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Run ID: bfd472a1-146f-4106-b535-cad8ec4cbdfc

📥 Commits

Reviewing files that changed from the base of the PR and between acfc616 and 7e8e19c.

📒 Files selected for processing (4)

• infra/relay/migrations/postgres/20260918175607_long_thread_ids/migration.sql
• infra/relay/migrations/postgres/20260918175607_long_thread_ids/snapshot.json
• infra/relay/src/http/Api.test.ts
• infra/relay/src/persistence/schema.ts

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📝 Walkthrough

Walkthrough

The relay HTTP router now accepts path parameters up to 512 characters. The worker applies this configuration. Relay persistence schemas and migrations support 512-character thread IDs. Integration tests cover UUID, long, and percent-encoded delegated thread IDs.

Changes

Relay thread ID support

Layer / File(s)	Summary
Router parameter limit and worker wiring infra/relay/src/http/Api.ts, infra/relay/src/worker.ts	The relay exports a 512-character router configuration. The worker passes this configuration to the HTTP router.
Persisted thread ID length infra/relay/src/persistence/schema.ts, infra/relay/migrations/postgres/20260918175607_long_thread_ids/migration.sql, infra/relay/migrations/postgres/20260918175607_long_thread_ids/snapshot.json	Activity and delivery thread_id columns now use varchar(512). The migration casts existing values, and the schema snapshot records the updated database definitions.
Delegated thread routing integration test infra/relay/src/http/Api.test.ts	The test verifies HTTP 200 responses, activity publication, preserved thread IDs, environment metadata, public keys, null state, and signature verification for UUID, 512-character, and percent-encoded delegated thread IDs.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant Client
  participant HttpRouter
  participant ServerRouter
  participant AgentActivityPublisher
  Client->>HttpRouter: Send request with thread ID
  HttpRouter->>ServerRouter: Route path parameter up to 512 characters
  ServerRouter->>AgentActivityPublisher: Publish activity with original thread ID and environment
  AgentActivityPublisher-->>ServerRouter: Complete publication
  ServerRouter-->>Client: Return HTTP 200

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Merge Risk: ⚪ Minimal · up to 7e8e1

The available evidence identifies no remaining actionable risk for supported long or percent-encoded thread IDs.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 4…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely describes the main change: accepting delegated thread IDs in relay activity routes.
Description check	✅ Passed	The description explains what changed, why it changed, test coverage, and the absence of UI changes. It does not reproduce the template headings or checklist, but it provides the required substantive …

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