Askit Build Subagent

askit-build-subagent

Purpose

Author conformant subagents. Two modes: create scaffolds a new agents/.md (frontmatter + role body); improve raises an existing subagent toward the quality bar. Subagents are Claude-only for plugin distribution (Codex v0.135 plugins cannot ship [agents.*]; Standard sec 3.3), so this skill emits no Codex artifact. Authoring depth is in [references/authoring-subagents.md](references/authoring-subagents.md).

When to use

When the user asks to create, scaffold, write, or improve a subagent (an agents/.md delegate).

create mode

1. Brief interview: ask for the subagent name (kebab-case), the bounded job it owns, the narrowest tools it needs, and which components (if any) it may invoke. Skip the interview if these inputs are already in context.
2. Copy templates/agent.md into agents/.md.
3. Fill the frontmatter: name equal to the file basename; a description that states what AND when (Standard sec 8.1); tools as the narrowest set (sec 9); optional model; chain listing components it may invoke (omit if none); metadata.version, metadata.tier, metadata.status, and metadata.agent-targets: [claude] (sec 3.3 - subagents are Claude-only for plugin distribution).
4. Register the subagent in library.json components.subagents as { name, path, version, tier, status }.
5. If the subagent declares a chain, add the entry to agents/_chain-permitted.yaml (: [, ...]) so S4 has no orphan.
6. Assess with node scripts/evaluate.mjs . --json and iterate until 0 errors (S3 components index + S4 chain contract must be clean).

improve mode

1. Run node scripts/evaluate.mjs . --json and read the report.
2. For each finding: an S3 error -> declare/undeclare the subagent in components.subagents to match disk; an S4 orphan -> add the missing caller -> callee to agents/_chain-permitted.yaml; an S4 phantom (the contract names a component not on disk) -> remove that contract entry, fix a misspelled name, or create the missing component. For any other finding, read its message and apply the fix it states.
3. Re-run evaluate to confirm.

Scope

Claude-only: a subagent is agents/.md (Claude auto-discovers it). Codex does not ingest plugin-shipped subagents (Standard sec 3.3), so there is no Codex render. Authoring is performed inline by the running agent; the toolkit's own askit-skill-author subagent is the delegated authoring role for skills.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: product-on-purpose
• Source: product-on-purpose/agent-skills-toolkit
• License: Apache-2.0
• Homepage: https://product-on-purpose.github.io/agent-skills-toolkit

Install and usage instructions live in the source repository linked above.