Pin Copilot CLI default back to 1.0.83 to fix instant HTTP 400 regression in 1.0.85 by Copilot · Pull Request #62421 · github/gh-aw

Copilot · 2026-09-21T18:00:49Z

Copilot CLI 1.0.85 returns an instant HTTP 400 "Bad Request" on the very first /responses request for some workflow shapes, failing agent runs before any tokens are consumed. Diffing compiled workflows between the last known-good release and the broken one showed the Copilot CLI version bump (1.0.80 → 1.0.85) as the only relevant change, so this reverts the default/compatible version to 1.0.83 pending an upstream fix.

Version pin revert

pkg/constants/version_constants.go: DefaultCopilotVersion reverted from 1.0.85 to 1.0.83, with a comment noting the regression and the issue link.
.github/aw/compat.json: agent-compat-v1 copilot row max-agent capped at 1.0.83 so the compat-matrix resolution path (used by already-pinned workflows) also avoids 1.0.85.
actions/setup/sh/install_copilot_cli.sh: baked-in DEFAULT_COPILOT_VERSION fallback synced to match via scripts/sync-compat.sh.

Tests & changelog

pkg/constants/version_constants_test.go updated to expect 1.0.83.
Added a changeset documenting the regression and the revert.

Generated workflows

Recompiled all workflow .lock.yml files; the only diffs are 1.0.85 → 1.0.83 version strings in the baked-in engine metadata.

Fixes Copilot CLI 1.0.85 (gh-aw v0.89.17) returns instant HTTP 400 on first request, breaking agent runs #62363

…n 1.0.85 Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

pelikhan · 2026-09-21T19:55:29Z

/smoke-copilot

pelikhan · 2026-09-21T19:55:36Z

@copilot resolve the merge conflicts in this pull request

github-actions · 2026-09-21T19:56:08Z

📰 BREAKING: Smoke Copilot is now investigating this issue comment. Sources say the story is developing...

…on-first-request # Conflicts: # .github/workflows/daily-testify-uber-super-expert.lock.yml Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot · 2026-09-21T20:04:25Z

@copilot resolve the merge conflicts in this pull request

Merged origin/main into this branch in 7da039d.

The only conflict was .github/workflows/daily-testify-uber-super-expert.lock.yml, where main had changed the workflow's frontmatter while this branch changed the baked-in engine version. Since lock files are generated, I took main's source and re-ran make recompile, so the resulting lock file carries main's frontmatter hash with "copilot":"1.0.83".

Verified afterwards: no .lock.yml still references 1.0.85, all 299 workflows compile, and make agent-report-progress reports lock files in sync with their markdown sources.

github-actions · 2026-09-21T20:09:07Z

🔧 Smoke Test: Copilot Engine — PR #62421

PR: Pin Copilot CLI default back to 1.0.83 to fix instant HTTP 400 regression in 1.0.85

Overall: PASS (1 non-blocking infra failure)

cc @pelikhan @Copilot

Warning

Firewall blocked 7 domains

The following domains were blocked by the firewall during workflow execution:

accounts.google.com
android.clients.google.com
clients2.google.com
contentautofill.googleapis.com
update.googleapis.com
www.google.com
www.gstatic.com

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

network:
  allowed:
    - defaults
    - "accounts.google.com"
    - "android.clients.google.com"
    - "clients2.google.com"
    - "contentautofill.googleapis.com"
    - "update.googleapis.com"
    - "www.google.com"
    - "www.gstatic.com"

See Network Configuration for more information.

📰 BREAKING: Report filed by Smoke Copilot · copilot · auto · 56.7 AIC · ⌖ 3.21 AIC · ⊞ 9.9K · ◷
_{Comment /smoke-copilot to run again}
_{Add label smoke to run again}

github-actions · 2026-09-21T20:09:12Z

Comment Memory

Tests run in the dark
Copilot checks every line
Green light, all is well

Note

This comment is managed by comment memory.

It stores persistent context for this thread in the code block at the top of this comment.
Edit only the text inside the backtick fences; workflow metadata and the footer are regenerated automatically.

Learn more about comment memory

Warning

Firewall blocked 7 domains

The following domains were blocked by the firewall during workflow execution:

accounts.google.com
android.clients.google.com
clients2.google.com
contentautofill.googleapis.com
update.googleapis.com
www.google.com
www.gstatic.com

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

network:
  allowed:
    - defaults
    - "accounts.google.com"
    - "android.clients.google.com"
    - "clients2.google.com"
    - "contentautofill.googleapis.com"
    - "update.googleapis.com"
    - "www.google.com"
    - "www.gstatic.com"

See Network Configuration for more information.

📰 BREAKING: Report filed by Smoke Copilot · copilot · auto · 56.7 AIC · ⌖ 3.21 AIC · ⊞ 9.9K · ◷
_{Comment /smoke-copilot to run again}
_{Add label smoke to run again}

github-actions

Smoke test: automated review submission test (COMMENT event, no approval).

Warning

Firewall blocked 7 domains

The following domains were blocked by the firewall during workflow execution:

accounts.google.com
android.clients.google.com
clients2.google.com
contentautofill.googleapis.com
update.googleapis.com
www.google.com
www.gstatic.com

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

network:
  allowed:
    - defaults
    - "accounts.google.com"
    - "android.clients.google.com"
    - "clients2.google.com"
    - "contentautofill.googleapis.com"
    - "update.googleapis.com"
    - "www.google.com"
    - "www.gstatic.com"

See Network Configuration for more information.

📰 BREAKING: Report filed by Smoke Copilot · copilot · auto · 56.7 AIC · ⌖ 3.21 AIC · ⊞ 9.9K
_{Comment /smoke-copilot to run again}
_{Add label smoke to run again}

github-actions · 2026-09-21T20:09:18Z

+// instant HTTP 400 ("Bad Request") on the very first /responses request for some
+// workflow shapes (see github/gh-aw#62363). Do not bump past 1.0.83 until that
+// regression is confirmed fixed upstream.
+const DefaultCopilotVersion Version = "1.0.83"


Smoke test: verifying inline review comment tooling. Confirms DefaultCopilotVersion revert to 1.0.83.

github-actions · 2026-09-21T20:59:24Z

✅ This PR looks great! The Copilot SWE agent has made a focused fix for the HTTP 400 regression introduced in Copilot CLI 1.0.85. The version revert is well-documented, tests have been updated, and all related workflow lock files have been recompiled. Ready for review.

Warning

Firewall blocked 1 domain

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

github.com

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

network:
  allowed:
    - defaults
    - "github.com"

See Network Configuration for more information.

Generated by ✅ Contribution Check · copilot · auto · 50.1 AIC · ⌖ 13.5 AIC · ⊞ 9.2K · ◷

Copilot

Copilot review overview

🟡 Changes recommended

The compatibility row remains open to automated version bumps, allowing the quarantined release to be reintroduced.

Get a fresh assessment by requesting another Copilot review.

Review effort: Balanced
Findings: 1

Open (1)

Freeze rollback row to prevent automated max-agent bumps · New

What changed in this PR

Pins Copilot CLI to 1.0.83 to avoid the reported 1.0.85 HTTP 400 regression.

Changes:

Downgrades the default, installer fallback, and compatibility maximum.
Updates tests and adds a patch changeset.
Regenerates affected workflow lock metadata.

File	Description
`pkg/constants/version_constants.go`	Pins Copilot CLI to 1.0.83.
`pkg/constants/version_constants_test.go`	Updates the expected version.
`actions/setup/sh/install_copilot_cli.sh`	Updates the installer fallback.
`.github/aw/compat.json`	Caps compatibility at 1.0.83.
`.changeset/patch-revert-copilot-cli-1.0.85-http400.md`	Documents the rollback.
`.github/workflows/workflow-skill-extractor.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/weekly-editors-health-check.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/visual-regression-checker.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/uk-ai-operational-resilience.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/ubuntu-image-analyzer.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/squad.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/squad-plan.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/squad-game-planner.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/smoke-workflow-call.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/smoke-multi-pr.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/smoke-issues.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/smoke-copilot-small.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/smoke-copilot-sdk.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/smoke-copilot-mai.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/smoke-copilot-auto.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/smoke-checkout-pr-dispatch.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/security-compliance.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/pr-nitpick-reviewer.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/pr-description-caveman.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/objective-impact-report.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/mergefest.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/layout-spec-maintainer.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/firewall.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/daily-trajectory-grader-implementer.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/daily-team-status.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/daily-spec-coverage-kiro.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/daily-schema-audit-cursor.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/daily-regression-audit-kiro.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/daily-pr-review-cursor.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/daily-model-resolution.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/daily-malicious-code-scan.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/daily-github-docs-seo-optimizer.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/daily-byok-ollama-test.lock.yml`	Regenerates Copilot version metadata.
`.github/workflows/agent-persona-explorer.lock.yml`	Updates the detection-engine version metadata.

💡 Add a code-review agent skill for context-aware, tailored reviews. Learn more in the docs.

+        "max-agent": "1.0.83",
        "open": true


github-actions · 2026-09-23T04:52:05Z

🎉 This pull request is included in a new release.

Release: v0.89.20

Initial plan

9a2d0f3

Copilot AI assigned Copilot and pelikhan Sep 21, 2026

Copilot AI linked an issue Sep 21, 2026 that may be closed by this pull request

Copilot CLI 1.0.85 (gh-aw v0.89.17) returns instant HTTP 400 on first request, breaking agent runs #62363

Closed

Copilot started work on behalf of pelikhan September 21, 2026 18:08 View session

Pin Copilot CLI default back to 1.0.83 to avoid HTTP 400 regression i…

d582e79

…n 1.0.85 Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Fix instant HTTP 400 on first request in Copilot CLI~~ Pin Copilot CLI default back to 1.0.83 to fix instant HTTP 400 regression in 1.0.85 Sep 21, 2026

Copilot finished work on behalf of pelikhan September 21, 2026 18:24

Copilot AI requested a review from pelikhan September 21, 2026 18:24

Copilot started work on behalf of pelikhan September 21, 2026 19:56 View session

Merge remote-tracking branch 'origin/main' into copilot/fix-http-400-…

7da039d

…on-first-request # Conflicts: # .github/workflows/daily-testify-uber-super-expert.lock.yml Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot finished work on behalf of pelikhan September 21, 2026 20:04

github-actions Bot mentioned this pull request Sep 21, 2026

Smoke Test: Copilot - 35647911532 #62456

Closed

github-actions Bot reviewed Sep 21, 2026

View reviewed changes

github-actions Bot mentioned this pull request Sep 21, 2026

[Contribution Check Report] Contribution Check — 2026-09-21 #62280

Closed

pelikhan marked this pull request as ready for review September 21, 2026 21:02

Copilot AI balanced review requested due to automatic review settings September 21, 2026 21:02

pelikhan merged commit 211e201 into main Sep 21, 2026
20 checks passed

pelikhan deleted the copilot/fix-http-400-on-first-request branch September 21, 2026 21:02

Copilot started reviewing on behalf of pelikhan September 21, 2026 21:02 View session

Copilot AI reviewed Sep 21, 2026

View reviewed changes

Comment thread .github/aw/compat.json

Comment on lines +37 to 38

"max-agent": "1.0.83",

"open": true

github-actions Bot mentioned this pull request Sep 22, 2026

[instructions] Sync instruction files with release v0.89.17 #62592

Merged

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Pin Copilot CLI default back to 1.0.83 to fix instant HTTP 400 regression in 1.0.85 - #62421

Pin Copilot CLI default back to 1.0.83 to fix instant HTTP 400 regression in 1.0.85#62421
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Version pin revert

Tests & changelog

Generated workflows

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🔧 Smoke Test: Copilot Engine — PR #62421

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