Feature Request: Per-Mode Skill Whitelist Configuration #556

Problem (one or two sentences)

Currently, all skills registered in .skill-lock.json are globally visible across all modes. Although SKILL.md supports a modeSlugs frontmatter field to declare which modes a skill belongs to, the platform does not filter skills based on this field when building the available_skills list.

Manually adding modeSlugs to local skills/*/SKILL.md files is not a durable solution — well-known source updates overwrite local changes.

Context (who is affected and when)

When the source is updated

Desired behavior (conceptual, not technical)

Add project-level and user-level configuration mechanisms for declaring skill-to-mode binding relationships, thereby overriding the global registration information — without modifying any skill source files.

Constraints / preferences (optional)

No response

Request checklist

• I've searched existing Issues and Discussions for duplicates
• This describes a specific problem with clear context and impact

Zoo Code Task Links (optional)

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Acceptance criteria (optional)

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Proposed approach (optional)

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Trade-offs / risks (optional)

No response