Set Pi gateway context window for Copilot Claude Sonnet 5 by Copilot · Pull Request #63494 · github/gh-aw

Copilot · 2026-09-25T19:18:50Z

Pi treats aw-gateway as a custom provider, so its model entries do not inherit context limits from Pi’s built-in Copilot catalog. Without contextWindow, claude-sonnet-5 falls back to 128k and can compact conversation history well before its 1M-token capacity.

Gateway model metadata: Set contextWindow: 1000000 for GitHub Copilot’s claude-sonnet-5. Leave other models unchanged rather than assign unverified limits.
Coverage: Add tests for the generated models.json and for unknown or differently routed models.

Fixes pi_models_json.cjs registers aw-gateway models with no contextWindow, so pi falls back to a 128k default well below the real model's capacity #63240

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

pelikhan · 2026-09-25T19:43:20Z

@copilot add front matter field to configure context window on the engine element.

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

Copilot · 2026-09-25T20:12:44Z

@copilot add front matter field to configure context window on the engine element.

Implemented in 0faf820. engine.context-window is now parsed, documented in the schema, and passed into Pi gateway models.json generation with focused Go/JS coverage.

pelikhan · 2026-09-25T20:25:26Z

@copilot investigate if other agentic engines support this flag. Add boolean to agentic engine to notify if it is supported by the agentic engine. Raise warning if not supported.

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

Copilot · 2026-09-25T20:45:13Z

@copilot investigate if other agentic engines support this flag. Add boolean to agentic engine to notify if it is supported by the agentic engine. Raise warning if not supported.

Implemented in 202c3f8 (with additional coverage in 474c1bc). EngineCapabilities.ContextWindow now identifies support; Pi is enabled, and unsupported engines emit a warning when engine.context-window is set.

Copilot

Copilot review overview

🟡 Changes recommended

Inline and imported configurations can silently mishandle the new setting, and generated editor metadata is stale.

Get a fresh assessment by requesting another Copilot review.

Review effort: Balanced
Findings: 3 · 1

Open (4)

Validate context-window using resolved imported engine configuration · New
Apply context-window overrides to inline engine definitions · New
Define or remove behavior-engine context-window capability · New
Regenerate editor autocomplete metadata for context-window · New

What changed in this PR

Adds explicit Pi gateway context-window metadata, including the 1M-token limit for GitHub Copilot’s Claude Sonnet 5.

Changes:

Adds engine.context-window parsing, capability validation, schema, and documentation.
Emits context-window metadata in Pi’s generated models.json.
Adds Go and JavaScript coverage for defaults, overrides, and unsupported engines.

File	Description
`actions/setup/js/pi_models_json.cjs`	Resolves and emits Pi context windows.
`actions/setup/js/pi_models_json.test.cjs`	Tests model metadata generation.
`pkg/workflow/pi_engine.go`	Passes configured context windows to setup.
`pkg/workflow/pi_engine_test.go`	Tests Pi environment generation.
`pkg/workflow/engine.go`	Parses the new engine setting.
`pkg/workflow/engine_definition.go`	Adds declarative capability metadata and minor URL parsing cleanup.
`pkg/workflow/engine_config_test.go`	Tests engine capability support.
`pkg/workflow/engine_args_test.go`	Tests configuration extraction.
`pkg/workflow/compiler_orchestrator_tools.go`	Invokes capability validation.
`pkg/workflow/agentic_engine.go`	Adds the runtime capability and slice-access cleanup.
`pkg/workflow/agent_validation.go`	Warns for unsupported engines.
`pkg/workflow/agent_validation_model_test.go`	Tests capability warnings.
`pkg/parser/schemas/main_workflow_schema.json`	Defines `context-window` in frontmatter.
`docs/src/content/docs/reference/frontmatter-full.md`	Documents the new setting.

+	_, engineConfig, _ := c.ExtractEngineConfig(frontmatter)
+	if engineConfig == nil || engineConfig.ContextWindow == 0 || engine.GetCapabilities().ContextWindow {


 func applyReferencedEngineFields(config *EngineConfig, engineObj map[string]any, topLevel engineTopLevelConfig) {
 	applyEngineProviderFields(config, engineObj)
 	applyEnginePermissionMode(config, engineObj)
+	applyEngineContextWindowField(config, engineObj)


 type EngineCapabilitiesDefinition struct {
 	ToolsAllowlist       bool `yaml:"tools-allowlist,omitempty"`
 	MaxTurns             bool `yaml:"max-turns,omitempty"`
+	ContextWindow        bool `yaml:"context-window,omitempty"`


+            "context-window": {
+              "type": "integer",
+              "minimum": 1,
+              "description": "Optional model context window metadata for engines that need to register explicit model catalog entries. Supported by the Pi engine when generating its AWF gateway models.json; other engines ignore it and emit a warning."


gh-aw-bot · 2026-09-25T21:03:04Z

@copilot Please review the current head, address any remaining maintainer feedback, refresh the branch if needed, and continue with the pr-finisher skill.

Generated by 👨🍳 PR Sous Chef

Generated by 👨‍🍳 PR Sous Chef · pi · gpt54 · 25.1 AIC · ⌖ 8.84 AIC · ⊞ 9.3K · ◷
_{Comment /souschef to run again}

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

Copilot · 2026-09-25T21:19:22Z

@copilot Please review the current head, address any remaining maintainer feedback, refresh the branch if needed, and continue with the pr-finisher skill.

Generated by [👨🍳 PR Sous Chef](htt...

Addressed the remaining review feedback in 620113b:

The unsupported-engine context-window warning now uses the resolved EngineConfig, so imported engine settings also trigger it. Added a compile test with an imported engine: {id: codex, context-window: …}.
context-window is now parsed on inline engine definitions (engine.runtime.id), with a test for that path.
Removed context-window from behaviors.capabilities. The schema never allowed it there, and behavior-defined engines have no code that uses it.
Regenerated docs/public/editor/autocomplete-data.json. The regenerated file also picks up some older schema changes that hadn't been copied over yet.

make agent-report-progress passes locally. My push won't start CI, so a maintainer needs to re-run it.

github-actions · 2026-09-27T01:11:12Z

🎉 This pull request is included in a new release.

Release: v0.89.22

Initial plan

afc868d

Copilot AI assigned Copilot and pelikhan Sep 25, 2026

Copilot started work on behalf of pelikhan September 25, 2026 19:19 View session

Copilot AI linked an issue Sep 25, 2026 that may be closed by this pull request

pi_models_json.cjs registers aw-gateway models with no contextWindow, so pi falls back to a 128k default well below the real model's capacity #63240

Closed

Set Pi gateway context window for Copilot Claude Sonnet 5

580f87b

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

Copilot AI changed the title ~~[WIP] Fix aw-gateway model registration to include context window~~ Set Pi gateway context window for Copilot Claude Sonnet 5 Sep 25, 2026

Copilot finished work on behalf of pelikhan September 25, 2026 19:31

Copilot AI requested a review from pelikhan September 25, 2026 19:31

Copilot started work on behalf of pelikhan September 25, 2026 19:43 View session

Copilot AI and others added 6 commits September 25, 2026 19:57

Add engine context-window frontmatter support

07edd79

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

Address context-window validation feedback

52eb9b0

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

Clarify context-window validation cleanup

d80d621

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

Warn on invalid Pi context window

49836d4

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

Include invalid context-window value in warning

68941e1

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

Cover absent Pi context-window export

0faf820

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

Copilot finished work on behalf of pelikhan September 25, 2026 20:13

Copilot started work on behalf of pelikhan September 25, 2026 20:25 View session

Copilot AI and others added 2 commits September 25, 2026 20:41

Warn unsupported engine context windows

202c3f8

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

Cover omitted context-window warning

474c1bc

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

Copilot finished work on behalf of pelikhan September 25, 2026 20:45

pelikhan marked this pull request as ready for review September 25, 2026 20:51

Copilot AI balanced review requested due to automatic review settings September 25, 2026 20:51

Copilot started reviewing on behalf of pelikhan September 25, 2026 20:52 View session

Copilot AI reviewed Sep 25, 2026

View reviewed changes

github-actions Bot mentioned this pull request Sep 25, 2026

[pr-sous-chef] PR Sous Chef run report #63268

Closed

Copilot started work on behalf of gh-aw-bot September 25, 2026 21:03 View session

Honor resolved and inline engine context-window settings

620113b

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

Copilot finished work on behalf of gh-aw-bot September 25, 2026 21:19

Copilot AI requested a review from gh-aw-bot September 25, 2026 21:19

pelikhan merged commit 5ecd40a into main Sep 26, 2026
45 checks passed

pelikhan deleted the copilot/fix-aw-gateway-model-context-window branch September 26, 2026 05:22

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Set Pi gateway context window for Copilot Claude Sonnet 5 - #63494

Set Pi gateway context window for Copilot Claude Sonnet 5#63494
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		_, engineConfig, _ := c.ExtractEngineConfig(frontmatter)
		if engineConfig == nil \|\| engineConfig.ContextWindow == 0 \|\| engine.GetCapabilities().ContextWindow {

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Copilot review overview

🟡 Changes recommended

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Copilot AI commented Sep 25, 2026 •

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