feat(skills): support disable-model-invocation skill frontmatter by haacked · Pull Request #3776 · PostHog/code

haacked · 2026-07-23T23:38:35Z

Problem

Claude Code skills support disable-model-invocation: true in SKILL.md frontmatter: the agent never invokes the skill on its own — only an explicit user invocation (slash command or composer skill tag) runs it. The bundled agent CLI already honors the field at runtime (both locally and in cloud sandboxes, since skill bundles ship SKILL.md verbatim), but PostHog Desktop was blind to it: the field wasn't parsed, wasn't shown anywhere in the skills UI, and — worse — editing a skill in the manifest editor silently stripped it from the file.

Changes

parseSkillFrontmatter now extracts disable-model-invocation, exposed as an optional disableModelInvocation on SkillInfo.
serializeSkillMarkdown (the shared SKILL.md serialization contract) emits the field, so manifest saves round-trip it instead of dropping it.
Skills UI: a "Manual-only" badge on the skill card and detail panel, and a "Manual invocation only" toggle in the manifest editor.

Not covered: team skill publish/install — the team-skills API only stores name/description/body, so the flag doesn't survive that round trip yet.

Related (different feature, no overlap): #3735 adds always-on skills.

How did you test this?

New unit tests for frontmatter parsing, serialization round-trip, and manifest save/clear of the flag (pnpm --filter @posthog/workspace-server exec vitest run src/services/skills: 111 passed).
pnpm --filter @posthog/ui exec vitest run src/features/skills passed.
pnpm typecheck for shared, workspace-server, host-router, ui, and web; Biome check on changed files.

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Created with PostHog Code

Parse the disable-model-invocation frontmatter field into SkillInfo, preserve it through manifest saves (previously editing a skill silently stripped it), emit it from serializeSkillMarkdown, and surface it in the skills UI as a badge plus an edit toggle. Generated-By: PostHog Code Task-Id: b9824961-d68a-4ac2-b272-7053ecc0e497

trunk-io · 2026-07-23T23:38:39Z

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github-actions · 2026-07-23T23:39:07Z

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit ad3a970.}

posthog · 2026-07-23T23:44:54Z

🦔 ReviewHog reviewed this pull request

Found 1 must fix, 0 should fix, 0 consider.

Published 1 finding (view the review).

posthog · 2026-07-24T00:17:38Z

ReviewHog Alpha 🦔 If you find any issues helpful - please reply "valid", "invalid", etc., for evaluation purposes 🙏

posthog

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Changes

Issues: 1 issue

Files (8)

packages/shared/src/skills.ts
packages/ui/src/features/skills/SkillCard.tsx
packages/ui/src/features/skills/SkillDetailPanel.tsx
packages/ui/src/features/skills/SkillManifestEditor.tsx
packages/workspace-server/src/services/skills/parse-skill-frontmatter.ts
packages/workspace-server/src/services/skills/schemas.ts
packages/workspace-server/src/services/skills/skill-discovery.ts
packages/workspace-server/src/services/skills/skills.ts

…invocation A value like `disable-model-invocation: true # manual only` misparsed to false because extractYamlValue keeps trailing comments, and a later manifest save would then silently drop the field from disk. Strip an unquoted trailing comment before the boolean comparison and cover the commented forms with tests. Generated-By: PostHog Code Task-Id: b9824961-d68a-4ac2-b272-7053ecc0e497

greptile-apps · 2026-07-24T00:24:33Z

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
packages/workspace-server/src/services/skills/parse-skill-frontmatter.ts:36-37
**Quoted scalar content becomes boolean**

When a hand-authored manifest contains a quoted non-boolean value such as `disable-model-invocation: "true # manual only"`, comment stripping removes the quoted suffix before validation, causing the UI to enable the setting and a subsequent save to rewrite it as boolean `true`.

_{Reviews (1): Last reviewed commit: "fix(skills): strip trailing YAML comment..." | Re-trigger Greptile}

greptile-apps · 2026-07-24T00:24:36Z

+  const withoutComment = value.replace(/\s+#.*$/, "").trim();
+  return unquoteYamlScalar(withoutComment).toLowerCase() === "true";


Quoted scalar content becomes boolean

When a hand-authored manifest contains a quoted non-boolean value such as disable-model-invocation: "true # manual only", comment stripping removes the quoted suffix before validation, causing the UI to enable the setting and a subsequent save to rewrite it as boolean true.

Prompt To Fix With AI

This is a comment left during a code review. Path: packages/workspace-server/src/services/skills/parse-skill-frontmatter.ts Line: 36-37 Comment: **Quoted scalar content becomes boolean** When a hand-authored manifest contains a quoted non-boolean value such as `disable-model-invocation: "true # manual only"`, comment stripping removes the quoted suffix before validation, causing the UI to enable the setting and a subsequent save to rewrite it as boolean `true`. How can I resolve this? If you propose a fix, please make it concise.

veria-ai · 2026-07-24T00:29:20Z

    "---",
    `name: ${serializeSkillScalar(meta.name)}`,
    `description: ${serializeSkillScalar(meta.description)}`,
+    ...(meta.disableModelInvocation ? ["disable-model-invocation: true"] : []),


Medium: Manual-only is not enforced for Codex sessions

This writes only Claude's disable-model-invocation frontmatter, while Codex sessions link these same skill directories into CODEX_HOME. Codex controls automatic selection through policy.allow_implicit_invocation in agents/openai.yaml, so a skill can still be selected and run without an explicit invocation even though the UI labels it Manual-only. Generate the corresponding Codex policy when preparing skills, or scope the setting and UI guarantee to agents that enforce it.

veria-ai · 2026-07-24T00:29:28Z

PR overview

Adds support for the disable-model-invocation skill frontmatter so skills can be designated as manually invoked.

The manual-only behavior is currently enforced for Claude sessions but not for Codex sessions, which use a separate implicit-invocation policy. As a result, Codex may still automatically select and run a skill that the UI labels Manual-only; no issues have yet been addressed.

Open issues (1)

Medium: Manual-only is not enforced for Codex sessions — packages/shared/src/skills.ts:64

Fixed/addressed: 0 · PR risk: 4/10

Comment stripping in parseYamlBoolean ran on the already-unquoted value, so a quoted non-boolean like "true # manual only" was mangled into boolean true. Move comment handling into extractYamlValue's plain-scalar path (quoted content is literal in YAML and never contains a comment) and add a regression test. Generated-By: PostHog Code Task-Id: b9824961-d68a-4ac2-b272-7053ecc0e497

github-actions · 2026-07-31T12:39:52Z

This PR has had no activity for 7 days and has been marked stale. We are moving to the monorepo and tightening PR staleness in preparation, so it will be closed in 7 days if no further activity occurs.

charlesvien · 2026-08-03T00:12:32Z

Remade in the monorepo as PostHog/posthog#76464 (PostHog/code main is frozen after the desktop import).

haacked added the reviewhog ($$$) Reviews pull requests before humans do label Jul 23, 2026

posthog Bot reviewed Jul 24, 2026

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Comment thread packages/workspace-server/src/services/skills/parse-skill-frontmatter.ts

haacked marked this pull request as ready for review July 24, 2026 00:21

haacked requested a review from a team July 24, 2026 00:21

greptile-apps Bot reviewed Jul 24, 2026

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veria-ai Bot reviewed Jul 24, 2026

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github-actions Bot added the stale No recent changes to PR label Jul 31, 2026

charlesvien mentioned this pull request Aug 3, 2026

feat(skills): support disable-model-invocation skill frontmatter PostHog/posthog#76464

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feat(skills): support disable-model-invocation skill frontmatter - #3776

feat(skills): support disable-model-invocation skill frontmatter#3776
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		const withoutComment = value.replace(/\s+#.*$/, "").trim();
		return unquoteYamlScalar(withoutComment).toLowerCase() === "true";

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haacked commented Jul 23, 2026

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veria-ai Bot commented Jul 24, 2026

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