Retry Anthropic requests after deprecated anthropic-beta header rejection

[Copilot]

Anthropic now rejects deprecated anthropic-beta values such as context-1m-2025-08-07, which causes Copilot CLI requests to fail with a 400 and exhaust retries. This change teaches the API proxy to detect that specific rejection, strip only the invalid beta value, and retry once.

• Proxy retry path

  • Detect Anthropic 400 responses matching:
    Unexpected value(s) \` for the `anthropic-beta` header`
  • Retry the same request once after removing only the rejected beta value
  • Remove the header entirely when stripping leaves it empty

• In-memory learning

  • Cache rejected beta values for the lifetime of the proxy process
  • Proactively remove learned deprecated values from subsequent Anthropic requests to avoid the extra round-trip

• Observability

  • Emit warning logs when deprecated beta values are stripped, including whether the strip happened on the retry path or from cached knowledge

• Regression coverage

  • Add focused proxy tests for:
    • first-hit 400 -> strip -> single retry
    • subsequent requests proactively stripping learned deprecated values

// Before
anthropic-beta: context-1m-2025-08-07,other-beta

// After Anthropic rejects context-1m-2025-08-07
anthropic-beta: other-beta

[github-actions]

✅ Coverage Check Passed

Overall Coverage

Metric	Base	PR	Delta
Lines	96.06%	96.13%	📈 +0.07%
Statements	95.89%	95.96%	📈 +0.07%
Functions	97.96%	97.96%	➡️ +0.00%
Branches	89.60%	89.64%	📈 +0.04%

📁 Per-file Coverage Changes (1 files)

File	Lines (Before → After)	Statements (Before → After)
src/config-writer.ts	83.0% → 85.6% (+2.54%)	83.0% → 85.6% (+2.54%)

---

Coverage comparison generated by scripts/ci/compare-coverage.ts

[Copilot]

Pull request overview

This PR updates the API proxy’s Anthropic request handling to recover from upstream 400s caused by deprecated anthropic-beta header values by stripping the rejected value, retrying once, and caching learned deprecated values for subsequent requests.

Changes:

• Detect Anthropic 400 responses indicating a deprecated anthropic-beta value, strip only the rejected value, and retry the request once.
• Cache deprecated beta values in-memory and proactively strip them from later requests, with warning logs for both retry and cached-strip paths.
• Add regression tests covering the retry behavior and the proactive stripping behavior.

Show a summary per file

File	Description
containers/api-proxy/proxy-request.js	Adds deprecated anthropic-beta detection, single-retry stripping behavior, in-memory caching, and warning logs.
containers/api-proxy/server.proxy.test.js	Adds focused tests for Anthropic deprecated beta handling and introduces per-test reset plumbing for the new cache.

Copilot's findings

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• Files reviewed: 2/2 changed files
• Comments generated: 2

[github-actions]

✅ Smoke Test Results

• GitHub API: ✅ 2 PR entries verified
• GitHub check: ✅ playwright_check PASS
• File verify: ✅ smoke-test file exists

Overall: PASS — Claude engine validation complete.

💥 [THE END] — Illustrated by Smoke Claude

[github-actions]

Smoke Test: Copilot BYOK (Offline) Mode

PR #3657: Retry Anthropic requests after deprecated anthropic-beta header rejection
Author: @Copilot | Assignees: @lpcox, @Copilot

✅ GitHub MCP - Successfully queried PRs
❌ GitHub.com connectivity - Pre-step data unavailable
❌ File write/read - File not found at expected path
✅ BYOK inference - Running successfully in offline mode

Note: Running in BYOK offline mode (COPILOT_OFFLINE=true) via api-proxy → api.githubcopilot.com

Status: ⚠️ PARTIAL (inference working, pre-step validation incomplete)

🔑 BYOK report filed by Smoke Copilot BYOK

[github-actions]

📡 API Proxy OTEL Tracing Smoke Test Results

✅ Scenario 1: Module Loading — otel.js loaded successfully, exports: startRequestSpan, setTokenAttributes, endSpan, endSpanError, shutdown, isEnabled + internals

✅ Scenario 2: Test Suite — All 32 OTEL tests passed (span creation, token attributes, parent context, OTLP export, file export)

✅ Scenario 3: Env Var Forwarding — src/services/api-proxy-service.ts forwards OTEL_EXPORTER_OTLP_ENDPOINT and GITHUB_AW_OTEL_TRACE_ID to api-proxy container

✅ Scenario 4: Token Tracker Integration — token-tracker-http.js has onUsage callback (OTEL hook point confirmed)

⚠️ Scenario 5: OTEL Diagnostics — No OTEL span file found (api-proxy OTEL not yet active in this run). Token usage tracking confirmed working (2,975 bytes logged).

Summary

All infrastructure tests passing. OTEL module, test suite, env forwarding, and integration points are validated. OTEL tracing not yet active in runtime (expected during development — requires endpoint config and explicit activation).

📡 OTel tracing validated by Smoke OTel Tracing

[github-actions]

PR titles: Refactor agent volume assembly into focused mount modules; Refactor Squid config generation into focused modules; Retry Anthropic requests after deprecated anthropic-beta header rejection
✅ GitHub PR review
❌ Safe Inputs GH CLI (safeinputs-gh unavailable)
✅ Playwright, file write/read, discussion, build
❌ Tavily search (no search tool exposed)
Overall status: FAIL

Warning

Firewall blocked 1 domain

The following domain was blocked by the firewall during workflow execution:

• registry.npmjs.org

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "registry.npmjs.org"

See Network Configuration for more information.

🔮 The oracle has spoken through Smoke Codex

[github-actions]

Smoke test FAIL

Warning

Firewall blocked 1 domain

The following domain was blocked by the firewall during workflow execution:

• localhost

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "localhost"

See Network Configuration for more information.

💎 Faceted by Smoke Gemini

[github-actions]

Chroot Runtime Version Test Results

The chroot environment test compared runtime versions between the host and the chrooted environment:

Runtime	Host Version	Chroot Version	Match?
Python	Python 3.12.13	Python 3.12.3	❌ NO
Node.js	v24.15.0	v22.22.3	❌ NO
Go	go1.22.12	go1.22.12	✅ YES

Result: Tests did not fully pass. Python and Node.js versions differ between the host runner environment and the chrooted agent container.

Context: These version differences are expected when the agent container uses a different base image (Ubuntu 22.04) than the GitHub Actions runner. The chroot test verifies that runtimes are accessible and functional within the chroot environment, even if versions differ.

Tested by Smoke Chroot

[github-actions]

Service Connectivity Test Results

❌ Redis: Connection timeout
❌ PostgreSQL (pg_isready): No response
❌ PostgreSQL (SELECT 1): Connection timeout

Overall: FAIL — All service checks failed. Services are unreachable at host.docker.internal.

🔌 Service connectivity validated by Smoke Services

[github-actions]

🏗️ Build Test Suite Results

Ecosystem	Project	Build/Install	Tests	Status
Bun	elysia	✅	1/1 passed	✅ PASS
Bun	hono	✅	1/1 passed	✅ PASS
C++	fmt	✅	N/A	✅ PASS
C++	json	✅	N/A	✅ PASS
Deno	oak	N/A	1/1 passed	✅ PASS
Deno	std	N/A	1/1 passed	✅ PASS
.NET	hello-world	✅	N/A	✅ PASS
.NET	json-parse	✅	N/A	✅ PASS
Go	color	✅	1/1 passed	✅ PASS
Go	env	✅	1/1 passed	✅ PASS
Go	uuid	✅	1/1 passed	✅ PASS
Java	gson	✅	1/1 passed	✅ PASS
Java	caffeine	✅	1/1 passed	✅ PASS
Node.js	clsx	✅	1/1 passed	✅ PASS
Node.js	execa	✅	1/1 passed	✅ PASS
Node.js	p-limit	✅	1/1 passed	✅ PASS
Rust	fd	✅	1/1 passed	✅ PASS
Rust	zoxide	✅	1/1 passed	✅ PASS

Overall: 8/8 ecosystems passed — ✅ PASS

All builds and tests completed successfully across all 18 projects in 8 ecosystems.

Generated by Build Test Suite for issue #3657 · ● 14.8M · ◷

[github-actions]

Smoke Test Results

✅ GitHub MCP – PR #3657: Retry Anthropic requests after deprecated anthropic-beta header rejection
✅ GitHub.com – HTTP 200
✅ File I/O – Write/read verified

Status: PASS 🎉

@lpcox

📰 BREAKING: Report filed by Smoke Copilot