[Martin Aeschlimann (aeschli)]

Follow-up to merged #343651, now based on main. This draft deprecates the Local hook format and updates Configure Hooks so newly generated Copilot files use the recommended format. The command-validation fix is already on main and is not part of this PR's diff.

Changes

• Keep Local-format hook files valid, but add a deprecation warning recommending version: 1, CLI event names, and timeoutSec.
• Change the default JSON schema snippet to the CLI format.
• Update both new-file creation paths in Configure Hooks to write versioned camelCase Copilot files with a cross-platform command placeholder. Claude files retain their nested format, and existing Local files retain their naming convention.
• Honor version when adding events to an empty CLI file.
• Register the runtime-supported preCompact and subagentStart names so generated hooks remain discoverable and receive schema metadata.
• Add thirteen tests covering generated files for all eleven hook types, parser round trips, and unchanged Claude structure.

Required Before Ready for Review

• Define and test input/output compatibility during migration of existing files. The runtime normalizes PascalCase aliases and adds _vsCodeCompat, which affects payload mapping; changing only names/version/timeout is not necessarily behavior-preserving. This draft does not automatically migrate existing files.
• Add behavioral JSON language-service validation tests for deprecation diagnostics and the default snippet.
• Validate the Configure Hooks workflow in the running workbench, including editor selection and existing-file updates.

The native runtime was checked separately: both PascalCase and camelCase configurations for PreCompact/SubagentStart load successfully. Runtime support is not the blocker.

Validation

• After chat: fix CLI hook command validation #343651 merged, merged main (3bc96745d641) in 4bcc64dc9ef and resolved the schema-test conflict, preserving both the upstream command-validation test and this draft's deprecation/default-snippet tests. The remaining diff contains only the follow-up changes.

• node build/next/index.ts transpile — passed against the updated sources.

• node test/unit/node/index.js --reporter dot --run src/vs/platform/agentPlugins/test/common/pluginParsers.test.ts --run src/vs/workbench/contrib/chat/test/common/promptSyntax/hookCompatibility.test.ts --run src/vs/workbench/contrib/chat/test/common/promptSyntax/hookSchema.test.ts — passed, 136 tests after the latest main merge.

• git diff --cached --check and normal pre-commit hygiene checks — passed for both update merges.

• The fast-build prerequisite check was blocked by an installed SDK/runtime version mismatch; dependency refresh was blocked by package-feed connectivity. The direct client transpile and targeted tests above succeeded; no new broad type-check was run.

• Feedback follow-up: plugin parsing now also canonicalizes preCompact and subagentStart, preserving their original event names and commands.

• node test/unit/node/index.js --run src/vs/platform/agentPlugins/test/common/pluginParsers.test.ts --run src/vs/workbench/contrib/chat/test/common/promptSyntax/hookCompatibility.test.ts --run src/vs/workbench/contrib/chat/test/common/promptSyntax/hookSchema.test.ts — passed, 131 tests after the feedback fix; client compilation also passed.

• node build/eslint.ts src/vs/platform/agentPlugins/common/pluginParsers.ts src/vs/platform/agentPlugins/test/common/pluginParsers.test.ts and node build/hygiene.ts src/vs/platform/agentPlugins/common/pluginParsers.ts src/vs/platform/agentPlugins/test/common/pluginParsers.test.ts — both passed; the normal pre-commit hook also passed.

• node build/next/build-fast.ts --client-only — passed.

• node test/unit/node/index.js --run src/vs/workbench/contrib/chat/test/common/promptSyntax/hookCompatibility.test.ts --run src/vs/workbench/contrib/chat/test/common/promptSyntax/hookSchema.test.ts — passed, 72 tests.

• node build/eslint.ts src/vs/workbench/contrib/chat/browser/promptSyntax/hookActions.ts src/vs/workbench/contrib/chat/common/promptSyntax/hookCompatibility.ts src/vs/workbench/contrib/chat/common/promptSyntax/hookTypes.ts src/vs/workbench/contrib/chat/test/common/promptSyntax/hookCompatibility.test.ts — passed, four files.

• node build/hygiene.ts src/vs/workbench/contrib/chat/browser/promptSyntax/hookActions.ts src/vs/workbench/contrib/chat/common/promptSyntax/hookCompatibility.ts src/vs/workbench/contrib/chat/common/promptSyntax/hookTypes.ts src/vs/workbench/contrib/chat/test/common/promptSyntax/hookCompatibility.test.ts — passed, four files; the normal pre-commit hook also passed.

• git diff --check — passed before commit.

• Standalone in-memory checks — all ten generated Copilot event configurations validate against the schema and remain discoverable. Earlier standalone Ajv validation also passed ten input cases on each split branch state and the baseline command-only regression check.

• ./scripts/test.sh --run src/vs/workbench/contrib/chat/test/common/promptSyntax/hookCompatibility.test.ts --run src/vs/workbench/contrib/chat/test/common/promptSyntax/hookSchema.test.ts --run src/vs/workbench/contrib/chat/test/browser/promptSyntax/hookActions.test.ts --run src/vs/workbench/contrib/chat/test/browser/promptSyntax/hookUtils.test.ts --reporter dot — Electron crashed before tests ran (exit 139).

• node test/unit/browser/index.js --run src/vs/workbench/contrib/chat/test/common/promptSyntax/hookCompatibility.test.ts --run src/vs/workbench/contrib/chat/test/common/promptSyntax/hookSchema.test.ts --run src/vs/workbench/contrib/chat/test/browser/promptSyntax/hookActions.test.ts --run src/vs/workbench/contrib/chat/test/browser/promptSyntax/hookUtils.test.ts --browser chromium --reporter dot — blocked by sandbox policy on loopback listening (EPERM ::1); browser tests were not run.

• Live UI, end-to-end migration, and broad type-checking were not run. No dependency manifests were changed.

Manual Checks

1. Configure a new hook and verify the generated JSON has version: 1, the correct CLI event name, and no Local-format deprecation warning; the command placeholder should be selected.
2. Repeat for PreCompact, SubagentStart, UserPromptSubmit, and Stop; verify generated events remain visible in Configure Hooks.
3. Add a hook to an empty versioned CLI file and verify its event uses CLI naming.
4. Verify existing Local files and Claude files retain their structure when adding hooks.
5. Verify the default CLI snippet has no schema diagnostics.

This draft targets main; the former stacked parent #343651 has merged.

[Copilot]

🟡 Changes recommended

The platform hook mapping omits preCompact and subagentStart aliases, causing plugin parsing to silently drop those events from generated configurations.

1 open issue

• Add missing camelCase hook aliases to plugin parser · New

What changed in this PR

Deprecates the Local hook JSON format while keeping it valid, and makes Configure Hooks generate the recommended Copilot CLI format. This builds on the stacked command-validation fix without automatically migrating existing files.

Changes:

• Add a Local-format deprecation warning and switch the default snippet to versioned CLI JSON.
• Centralize new-file generation, preserve Claude structure, and honor versioned empty files when adding events.
• Register two additional CLI event names and add generation, parser round-trip, and schema-structure tests.

File	Description
src/​vs/​workbench/​contrib/​chat/​test/​common/​promptSyntax/​hookSchema.test.ts	Check deprecation placement and default snippet structure.
src/​vs/​workbench/​contrib/​chat/​test/​common/​promptSyntax/​hookCompatibility.test.ts	Cover all ten generated Copilot events, discovery, and Claude structure.
src/​vs/​workbench/​contrib/​chat/​common/​promptSyntax/​hookTypes.ts	Register preCompact and subagentStart CLI names.
src/​vs/​workbench/​contrib/​chat/​common/​promptSyntax/​hookSchema.ts	Deprecate Local format and update the default snippet.
src/​vs/​workbench/​contrib/​chat/​common/​promptSyntax/​hookCompatibility.ts	Add a shared format-aware hook-file builder.
src/​vs/​workbench/​contrib/​chat/​browser/​promptSyntax/​hookActions.ts	Use the builder in both creation paths and honor existing file versions.

_{Review effort: Balanced}

[Copilot]

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