feat(copilot): support `model: auto`/`model: none` to bypass model pinning on automatic-selection plans by Copilot · Pull Request #46556 · github/gh-aw

Copilot · 2026-07-19T07:10:57Z

On Copilot Free (and similar plans limited to automatic model selection), every request fails with HTTP 400 because the engine always injects an explicit COPILOT_MODEL — which the gateway rejects for these plans. Setting model: gpt-5-mini or any other alias produces the same 400 since the plan disallows any pinned model.

Changes

New sentinels auto and none for engine.model — when either is set, the compiler omits COPILOT_MODEL from the step env entirely, letting the Copilot CLI use its native automatic routing.
- Constants: CopilotAutoModelSentinel = "auto", CopilotNoModelSentinel = "none" in pkg/constants/engine_constants.go
- addCopilotModelEnv in copilot_engine_execution.go returns early without setting COPILOT_MODEL for these values
Runtime defense-in-depth in resolve_model_alias.cjs — resolveConfiguredCopilotModel returns "" for auto/none (case-insensitive), and applyCopilotModelAliasResolution in the harness calls delete process.env.COPILOT_MODEL when it receives an empty resolution result, covering the case where someone sets the sentinel via engine.env

Usage

engine:
  id: copilot
  model: auto   # suppress COPILOT_MODEL; CLI auto-selects model

model: none is a synonym. Both values are inert with respect to alias resolution and bypass the org-variable fallback (GH_AW_MODEL_AGENT_COPILOT) as well.

Fixes Copilot engine unusable on plans limited to automatic model selection; pinning a model does not help #46531

Warning

Firewall blocked 1 domain

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

pi.dev

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

network:
  allowed:
    - defaults
    - "pi.dev"

See Network Configuration for more information.

Generated by 👨‍🍳 PR Sous Chef · 8.59 AIC · ⌖ 8.26 AIC · ⊞ 7.5K · ◷
_{Comment /souschef to run again}

Warning

Firewall blocked 1 domain

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

pi.dev

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

network:
  allowed:
    - defaults
    - "pi.dev"

See Network Configuration for more information.

Generated by 👨‍🍳 PR Sous Chef · 8.96 AIC · ⌖ 7.34 AIC · ⊞ 7.5K · ◷
_{Comment /souschef to run again}

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

…ng comment line Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

pelikhan · 2026-07-19T07:38:18Z

@copilot the BYOK route requires a model id

… in BYOK mode - `addCopilotModelEnv` now accepts `isBYOKMode bool`; when the `auto`/`none` sentinel is set and BYOK is active it falls through to the org-variable expression (with `CopilotBYOKDefaultModel` as final fallback) instead of skipping COPILOT_MODEL injection entirely. - `applyCopilotModelAliasResolution` in the JS harness now checks `COPILOT_PROVIDER_BASE_URL` before deleting COPILOT_MODEL for sentinel values; in BYOK mode the sentinel is ignored and COPILOT_MODEL is preserved. - Tests added for both the Go and JS paths. Fixes: https://github.com/github/gh-aw/pull/XXXXX#issuecomment-5014891414 Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

…for BYOK sentinel case Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot · 2026-07-19T08:00:22Z

@copilot the BYOK route requires a model id

Fixed. When model: auto or model: none is set alongside a BYOK configuration, the sentinel now has no effect and falls back to the org-variable expression with CopilotBYOKDefaultModel as the final fallback — the same model injection path used when no model is configured.

Two-layer fix committed in the latest push:

Go compiler (addCopilotModelEnv): when isBYOKMode is true and the sentinel is detected, it falls through to BuildModelOverrideExpression(...) instead of returning early, so COPILOT_MODEL is always injected for BYOK.
JS harness (applyCopilotModelAliasResolution): checks COPILOT_PROVIDER_BASE_URL before deleting COPILOT_MODEL for sentinel values — in BYOK mode the sentinel is ignored and the existing model value is preserved (defense-in-depth for engine.env.COPILOT_MODEL: auto).

The non-BYOK sentinel behaviour (Copilot Free auto-selection) is unchanged.

Copilot

Pull request overview

Adds Copilot automatic model routing for plans that reject explicitly pinned models.

Changes:

Adds auto and none model sentinels.
Omits or clears COPILOT_MODEL for automatic routing.
Adds Go and JavaScript coverage plus release notes.

Show a summary per file

File	Description
`pkg/workflow/model_env_vars_test.go`	Tests sentinel compilation behavior.
`pkg/workflow/copilot_engine_execution.go`	Handles sentinels when building step environments.
`pkg/constants/engine_constants.go`	Defines sentinel constants.
`actions/setup/js/resolve_model_alias.test.cjs`	Tests sentinel alias resolution.
`actions/setup/js/resolve_model_alias.cjs`	Resolves sentinels to no model.
`actions/setup/js/copilot_harness.test.cjs`	Tests runtime environment handling.
`actions/setup/js/copilot_harness.cjs`	Clears sentinels before Copilot execution.
`.changeset/patch-copilot-auto-model-sentinel.md`	Documents the user-facing fix.

Review details

Tip

Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

Files reviewed: 8/8 changed files
Comments generated: 3
Review effort level: Medium

pelikhan · 2026-07-19T08:46:46Z

@copilot update dev.md to use copilot auto and summarize the readme.

update 10 more agentic workflows to use auto model

…md to copilot auto; add model: auto to 10 workflows Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

gh-aw-bot · 2026-07-19T09:07:21Z

@copilot please run the pr-finisher skill, investigate and fix the failed checks below, refresh the branch if needed, and rerun checks.

Failed checks:

Warning

Firewall blocked 1 domain

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

pi.dev

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

network:
  allowed:
    - defaults
    - "pi.dev"

See Network Configuration for more information.

Generated by 👨‍🍳 PR Sous Chef · 8.59 AIC · ⌖ 8.26 AIC · ⊞ 7.5K · ◷
_{Comment /souschef to run again}

Copilot · 2026-07-19T09:08:32Z

@copilot update dev.md to use copilot auto and summarize the readme.

update 10 more agentic workflows to use auto model

Done in the latest commit:

dev.md switched from id: codex / model: gpt-5.4 to id: copilot / model: auto, with copilot-requests: write added to permissions.
10 agentic workflows updated to add model: auto to their copilot engine blocks: archie, artifacts-summary, brave, breaking-change-checker, ci-coach, code-scanning-fixer, copilot-cli-deep-research, copilot-opt, copilot-pr-merged-report, copilot-pr-nlp-analysis.
All 258 workflows recompiled successfully.

@copilot the BYOK route requires a model id

The BYOK sentinel handling is now fully corrected in the latest commit. When model: auto or model: none is set and BYOK mode is active (COPILOT_PROVIDER_BASE_URL present), the JS harness now replaces the sentinel with the concrete BYOK default model (claude-sonnet-4.6) in process.env.COPILOT_MODEL — so providers always receive a valid model ID. The corresponding tests, constant docs, and changeset notes have all been updated to document this BYOK exception.

…s.cjs Co-authored-by: gh-aw-bot <259018956+gh-aw-bot@users.noreply.github.com>

Copilot · 2026-07-20T02:03:36Z

@copilot please run the pr-finisher skill, address any unresolved review feedback, confirm the branch is current, and summarize the next concrete maintainer action.

_Run: https://github.com/github/...

All checks on run 29711510274 passed (all 6 jobs succeeded). Branch is current with main, all 3 review threads resolved, and local validation clean.

Next maintainer action: merge the PR.

pelikhan · 2026-07-20T04:18:29Z

/smoke-copilot

github-actions · 2026-07-20T04:18:59Z

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

pelikhan · 2026-07-20T04:29:08Z

@copilot make sure auto is configure in the awf command

https://github.com/github/gh-aw/actions/runs/29716577546/job/88271094667#step:48:1

gh-aw-bot · 2026-07-20T04:32:53Z

@copilot please run the pr-finisher skill, refresh the branch if needed, and summarize the next concrete maintainer action after the current smoke investigation completes.

Recent maintainer request:

investigate https://github.com/github/gh-aw/actions/runs/29716577546/job/88275858376#step:48:1

Run: https://github.com/github/gh-aw/actions/runs/29716826331

Warning

Firewall blocked 1 domain

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

pi.dev

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

network:
  allowed:
    - defaults
    - "pi.dev"

See Network Configuration for more information.

Generated by 👨‍🍳 PR Sous Chef · 13.4 AIC · ⌖ 6.26 AIC · ⊞ 7.5K · ◷
_{Comment /souschef to run again}

…e 258 workflows Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

pelikhan · 2026-07-20T04:56:19Z

/smoke-copilot

github-actions · 2026-07-20T04:56:57Z

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

pelikhan · 2026-07-20T05:05:40Z

@copilot remove experiments from smoke-copilot and set model: auto

github-actions · 2026-07-20T05:05:58Z

Comment Memory

Automation hums in moonlight
Green checks bloom across the code
Copilot ships the dawn

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

📰 BREAKING: Report filed by Smoke Copilot · 11.6 AIC · ⌖ 2.28 AIC · ⊞ 18.9K · ◷
_{Comment /smoke-copilot to run again}
_{Add label smoke to run again}

github-actions

Smoke test review: comments recorded; no blocking verdict.

📰 BREAKING: Report filed by Smoke Copilot · 11.6 AIC · ⌖ 2.28 AIC · ⊞ 18.9K
_{Comment /smoke-copilot to run again}
_{Add label smoke to run again}

pelikhan · 2026-07-20T05:15:23Z

@copilot resolve the merge conflicts on this branch.

Copilot · 2026-07-20T05:15:29Z

@pelikhan Unfortunately I hit an unexpected error while processing your comment. I've automatically reported this to GitHub.

You can ask me to try again later by mentioning me in a new comment.

If you want to contact GitHub about this error, please mention the following identifier so they can better serve you: 2be0a99e-9e11-4933-949f-cbdc0b6c050a

Sorry for the inconvenience!

Copilot · 2026-07-20T05:15:44Z

@pelikhan Unfortunately I hit an unexpected error while processing your comment. I've automatically reported this to GitHub.

You can ask me to try again later by mentioning me in a new comment.

If you want to contact GitHub about this error, please mention the following identifier so they can better serve you: 2be0a99e-9e11-4933-949f-cbdc0b6c050a

Sorry for the inconvenience!

Copilot · 2026-07-20T05:15:58Z

@pelikhan Unfortunately I hit an unexpected error while processing your comment. I've automatically reported this to GitHub.

You can ask me to try again later by mentioning me in a new comment.

If you want to contact GitHub about this error, please mention the following identifier so they can better serve you: 2be0a99e-9e11-4933-949f-cbdc0b6c050a

Sorry for the inconvenience!

Copilot · 2026-07-20T05:16:14Z

@pelikhan Unfortunately I hit an unexpected error while processing your comment. I've automatically reported this to GitHub.

You can ask me to try again later by mentioning me in a new comment.

If you want to contact GitHub about this error, please mention the following identifier so they can better serve you: 2be0a99e-9e11-4933-949f-cbdc0b6c050a

Sorry for the inconvenience!

Copilot · 2026-07-20T05:16:27Z

@pelikhan Unfortunately I hit an unexpected error while processing your comment. I've automatically reported this to GitHub.

You can ask me to try again later by mentioning me in a new comment.

If you want to contact GitHub about this error, please mention the following identifier so they can better serve you: 2be0a99e-9e11-4933-949f-cbdc0b6c050a

Sorry for the inconvenience!

Copilot · 2026-07-20T05:16:42Z

@pelikhan Unfortunately I hit an unexpected error while processing your comment. I've automatically reported this to GitHub.

You can ask me to try again later by mentioning me in a new comment.

If you want to contact GitHub about this error, please mention the following identifier so they can better serve you: 2be0a99e-9e11-4933-949f-cbdc0b6c050a

Sorry for the inconvenience!

Copilot · 2026-07-20T05:17:35Z

@copilot please run the pr-finisher skill, refresh the branch if needed, and summarize the next concrete maintainer action after the current smoke investigation completes.

Recent maintainer request...

Root cause investigated (run 29716577546, job 88271094667 — step 48 "Execute GitHub Copilot CLI"):

COPILOT_MODEL=auto was being resolved through the alias chain in the harness (auto → any → copilot/* → first-catalog-model), so the AWF proxy received a concrete model ID instead of auto. The AWF config already has "auto":["any"] configured, but the harness's resolveConfiguredCopilotModel was overriding it before the CLI made any requests.

Fix applied (commit 27e99d0 — local, push blocked by 403):

Added auto as a no-op pass-through sentinel in resolveConfiguredCopilotModel (actions/setup/js/resolve_model_alias.cjs):

// "auto" is a no-op pass-through sentinel: return it unchanged so the AWF proxy
// receives COPILOT_MODEL=auto and performs proxy-side automatic model selection.
if (configuredModel.toLowerCase() === "auto") {
  logger(`copilot model pass-through sentinel '${configuredModel}': skipping alias resolution for proxy-side automatic model selection`);
  return configuredModel;
}

This ensures COPILOT_MODEL=auto flows through to the AWF proxy unchanged — the proxy's "auto":["any"] config handles the routing. Updated test assertions in resolve_model_alias.test.cjs and copilot_harness.test.cjs. Local validation passes (258 workflows in sync, all targeted tests pass).

Blocker: engine-tools-report_progress is returning 403 on push — the change is committed locally as 27e99d0 but cannot be pushed. A maintainer needs to grant push access or push the commit manually.

pelikhan · 2026-07-20T05:17:47Z

@copilot resolve the merge conflicts on this branch.

Copilot · 2026-07-20T05:17:52Z

@pelikhan Unfortunately I hit an unexpected error while processing your comment. I've automatically reported this to GitHub.

You can ask me to try again later by mentioning me in a new comment.

If you want to contact GitHub about this error, please mention the following identifier so they can better serve you: 9cabca14-8223-4786-aea4-3c30ded347d3

Sorry for the inconvenience!

Copilot · 2026-07-20T05:18:07Z

@pelikhan Unfortunately I hit an unexpected error while processing your comment. I've automatically reported this to GitHub.

You can ask me to try again later by mentioning me in a new comment.

If you want to contact GitHub about this error, please mention the following identifier so they can better serve you: 9cabca14-8223-4786-aea4-3c30ded347d3

Sorry for the inconvenience!

Initial plan

7a8bf40

Copilot AI assigned Copilot and pelikhan Jul 19, 2026

Copilot AI linked an issue Jul 19, 2026 that may be closed by this pull request

Copilot engine unusable on plans limited to automatic model selection; pinning a model does not help #46531

Open

Copilot started work on behalf of pelikhan July 19, 2026 07:11 View session

Copilot AI and others added 2 commits July 19, 2026 07:32

feat: support auto/none sentinel for Copilot engine automatic model s…

a3e31e5

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

fix: use delete process.env.COPILOT_MODEL for sentinel; restore missi…

ccf9609

…ng comment line Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Fix copilot engine usability issue for free accounts~~ feat(copilot): support model: auto/model: none to bypass model pinning on automatic-selection plans Jul 19, 2026

Copilot finished work on behalf of pelikhan July 19, 2026 07:35

Copilot AI requested a review from pelikhan July 19, 2026 07:35

Copilot started work on behalf of pelikhan July 19, 2026 07:39 View session

Copilot AI and others added 2 commits July 19, 2026 07:57

fix: improve Go test to validate full org-variable expression format …

5797156

…for BYOK sentinel case Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot finished work on behalf of pelikhan July 19, 2026 08:00

pelikhan marked this pull request as ready for review July 19, 2026 08:42

Copilot AI review requested due to automatic review settings July 19, 2026 08:42

Copilot started reviewing on behalf of pelikhan July 19, 2026 08:42 View session

Copilot AI reviewed Jul 19, 2026

View reviewed changes

Comment thread actions/setup/js/copilot_harness.cjs Outdated

Comment thread .changeset/patch-copilot-auto-model-sentinel.md Outdated

Comment thread pkg/constants/engine_constants.go Outdated

Copilot started work on behalf of pelikhan July 19, 2026 08:47 View session

Copilot AI and others added 2 commits July 19, 2026 09:05

fix: BYOK sentinel replaces auto/none with default model; update dev.…

80dd022

…md to copilot auto; add model: auto to 10 workflows Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Merge branch 'main' into copilot/fix-copilot-engine-issue

aa2e309

github-actions Bot mentioned this pull request Jul 19, 2026

[pr-sous-chef] Run report — 0 nudged, 10 skipped #46494

Open

Copilot finished work on behalf of pelikhan July 19, 2026 09:09

Copilot started work on behalf of gh-aw-bot July 19, 2026 09:10 View session

fix: add trimleftright to README and fix JSDoc type cast in add_label…

c5d0ff1

…s.cjs Co-authored-by: gh-aw-bot <259018956+gh-aw-bot@users.noreply.github.com>

Copilot finished work on behalf of gh-aw-bot July 20, 2026 02:04

Copilot started work on behalf of pelikhan July 20, 2026 04:29 View session

fix: add auto to model_aliases.json; update wasm goldens and recompil…

825dfda

…e 258 workflows Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot finished work on behalf of pelikhan July 20, 2026 04:54

Copilot started work on behalf of gh-aw-bot July 20, 2026 04:55 View session

github-actions Bot reviewed Jul 20, 2026

View reviewed changes

Copilot finished work on behalf of gh-aw-bot July 20, 2026 05:18

Copilot started work on behalf of pelikhan July 20, 2026 05:19 View session

pelikhan closed this Jul 20, 2026

Copilot stopped work on behalf of pelikhan due to an error July 20, 2026 05:34
The session was cancelled by the user.

Uh oh!

Conversation

Copilot AI commented Jul 19, 2026 • edited by github-actions Bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Changes

Usage

Uh oh!

pelikhan commented Jul 19, 2026

Uh oh!

Copilot AI commented Jul 19, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Review details

Uh oh!

Uh oh!

Uh oh!

Uh oh!

pelikhan commented Jul 19, 2026

Uh oh!

gh-aw-bot commented Jul 19, 2026

Uh oh!

Copilot AI commented Jul 19, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Copilot AI commented Jul 20, 2026

Uh oh!

pelikhan commented Jul 20, 2026

Uh oh!

github-actions Bot commented Jul 20, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

pelikhan commented Jul 20, 2026

Uh oh!

gh-aw-bot commented Jul 20, 2026

Uh oh!

pelikhan commented Jul 20, 2026

Uh oh!

github-actions Bot commented Jul 20, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

pelikhan commented Jul 20, 2026

Uh oh!

github-actions Bot commented Jul 20, 2026

Comment Memory

Uh oh!

github-actions Bot left a comment

Choose a reason for hiding this comment

Uh oh!

pelikhan commented Jul 20, 2026

Uh oh!

Copilot AI commented Jul 20, 2026

Uh oh!

Copilot AI commented Jul 20, 2026

Uh oh!

Copilot AI commented Jul 20, 2026

Uh oh!

Copilot AI commented Jul 20, 2026

Uh oh!

Copilot AI commented Jul 20, 2026

Uh oh!

Copilot AI commented Jul 20, 2026

Uh oh!

Copilot AI commented Jul 20, 2026

Uh oh!

pelikhan commented Jul 20, 2026

Uh oh!

Copilot AI commented Jul 20, 2026

Uh oh!

Copilot AI commented Jul 20, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Copilot AI commented Jul 19, 2026 •

edited by github-actions Bot

Loading

Copilot AI commented Jul 19, 2026 •

edited

Loading

github-actions Bot commented Jul 20, 2026 •

edited

Loading

github-actions Bot commented Jul 20, 2026 •

edited

Loading