/new-skill — Author a Convention-Compliant Skill

Scaffold a new skill the way this template's gold-standard skills are written: a deep module behind a simple interface (Ousterhout, A Philosophy of Software Design — "deep modules": a small surface that hides substantial implementation). The user supplies a fuzzy intent; this skill interviews it into a tight spec, then writes .claude/skills/<name>/SKILL.md with frontmatter and body that are mutually consistent — so check-skill-integrity.py and check-surface-sync.sh pass without a second pass.

Adapted from the write-a-skill pattern in mattpocock/skills, reshaped to this repo's frontmatter, section, and gate conventions.

When to use

• You keep re-explaining the same 3+ step workflow to Claude and want it captured as a reusable slash command.
• You need a domain-specific check or output format (citation style, replication gate, a new review lens).
• You want a new skill that is consistent with the 40+ siblings in .claude/skills/ — same sections, same cross-reference style, same gate-passing frontmatter.

Use /learn instead when you just discovered something non-obvious this session and want it preserved — /learn captures a discovery; /new-skill deliberately designs an interface. With --from-learn, this skill upgrades a /learn-shaped stub into a full convention-compliant skill.

Phases

Phase 0 — Resolve the name and check for collisions

1. Take the kebab-case name from $0 (or ask). Reject non-kebab-case, names that collide with an existing .claude/skills/<name>/, or names that shadow a built-in (commit, learn, …) — ls .claude/skills/ and stop if taken.
2. Read templates/skill-template.md for the canonical structure and the frontmatter-field reference.
3. Skim 2-3 sibling skills near the intended domain (e.g. Glob .claude/skills/*/SKILL.md, then Read the closest matches) so the new skill borrows real conventions, not invented ones.

Phase 1 — Interview (collect everything before writing)

A skill cannot stop to ask mid-write, so gather all interactivity up front (the orchestrator-protocol.md RUN_CONFIG discipline). Ask, in one batch:

1. Purpose — one sentence: what does it accomplish and why does it exist?
2. Trigger phrases — the 4-7 quoted phrases a user would actually say. These become the description's "Use when…" clause and are what makes the skill auto-discoverable.
3. Inputs / arguments — positional args and any flags (each must become a documented --token).
4. Tools — does the body Read? Write? Grep/Glob? run Bash? fan out to a subagent (the Agent tool)? hit the web via WebSearch/WebFetch? Only declare what it actually uses.
5. Output — a written file (where?), a chat report, or an in-place edit? Should it be read-only?
6. Scope boundary — the one or two things it explicitly does NOT do (and which sibling owns those).

Echo a one-paragraph design brief back for confirmation before writing.

Phase 2 — Write the SKILL.md (deep module, simple interface)

Write .claude/skills/<name>/SKILL.md from the template, with these gold-standard sections:

• Frontmatter: name, description (third person, with the quoted trigger phrases), argument-hint, allowed-tools, effort. Add disable-model-invocation: true if it writes a persistent, load-bearing file (template's "when to disable" rule).
• Body sections: When to use, numbered Phases (or Steps), an Output / report format, Exit behavior, Cross-references (to real sibling files), What this skill does NOT do, and a ## Flags section if any flags are advertised.
• Keep the interface small (a few args) and the implementation deep (the phases carry the weight) — resist exposing a knob for every internal choice.

Phase 3 — Enforce parity so the gates pass first try

check-skill-integrity.py enforces two parities this phase must satisfy (.claude/scripts/ hosts the gate runners; scripts/check-skill-integrity.py is the checker):

• Flag parity (both directions). Every flag in argument-hint MUST appear in the body as a bare-backticked token, and every flag documented in the body MUST appear in argument-hint. So --from-learn and --dry-run are listed in the hint and described under ## Flags. A stale hint flag fails the gate as surely as a missing one.
• allowed-tools parity. The body may only invoke tools listed in allowed-tools. If a phase fans out to a subagent (the Agent tool), that tool must be in the list; if it never does, do not list it. This skill lists exactly Read, Write, Glob, Grep, Bash — the tools its phases use, and no subagent fan-out.
• Anchor resolution. Internal [text](path#anchor) links must resolve — only link to headings that exist.

Run python3 scripts/check-skill-integrity.py --verbose and fix any P0/P1 before declaring done.

Phase 4 — Remind: register the surface (table-row gate)

The skill is NOT discoverable to a reader until it is listed. check-surface-sync.sh runs a table-row gate: the <!-- surface-sync-table: skills --> table in README.md must have exactly one data row per skill on disk. Adding a skill without a row fails the gate.

REMIND the user to:

1. Add a row to the CLAUDE.md "Skills Quick Reference" table: | `/<name> [args]` | <what it does> |.
2. Add a row to the README.md skills table: | `/<name>` | <what it does> |.
3. Run ./scripts/check-surface-sync.sh and python3 scripts/check-skill-integrity.py — both must exit 0.

Print the two ready-to-paste rows so the user can drop them in.

Output / report format

• A new file at .claude/skills/<name>/SKILL.md.
• A chat summary: the resolved name, the design brief, the gate results (integrity + a reminder that surface-sync still needs the two table rows), and the two paste-ready table rows.
• With --dry-run: emit the proposed SKILL.md to chat only and write nothing.

Exit behavior

• Skill written, gates green: exit 0 with the path, the two table rows, and the explicit "now add those rows + run the two checks" reminder.
• Name collision or non-kebab-case: stop in Phase 0 with the conflict named; write nothing.
• check-skill-integrity.py reports P0/P1: fix in-place and re-run before returning; never hand back a skill that fails its own gate.
• --dry-run: print the draft, write nothing, exit 0.

Flags

• --from-learn — Seed the interview from an existing /learn-style stub (or the current session's discovery) and upgrade it into a full convention-compliant skill rather than starting blank.
• --dry-run — Produce the SKILL.md content in chat for review without writing it to disk or touching any surface table.

Cross-references

• templates/skill-template.md — the canonical structure, frontmatter-field reference, and the "when to set disable-model-invocation" rule this skill follows.
• .claude/skills/learn/SKILL.md — capture a session discovery (the lighter sibling); --from-learn upgrades its output.
• .claude/skills/coauthor-brief/SKILL.md — a gold-standard skill to imitate (interview → write → flags → exit-behavior shape).
• .claude/rules/orchestrator-protocol.md — why the interview collects all interactivity before writing.
• .claude/scripts/ and scripts/check-skill-integrity.py / scripts/check-surface-sync.sh — the gates this skill is built to pass on the first try.

What this skill does NOT do

• Capture a session discovery — that is /learn. This skill designs an interface; /learn records a finding.
• Edit the README / CLAUDE.md surface tables for you. It prints the two rows and reminds you; registering them (and re-running ./scripts/check-surface-sync.sh) is a deliberate human step so the surface gate is never silently satisfied.
• Write agents, rules, or hooks. It scaffolds a skill only; an agent goes in .claude/agents/, a rule in .claude/rules/.
• Commit anything. Branch / PR / merge is /commit's job.