loop-forge — stamp a guarded, reusable loop (/loop-forge)

Picture an engraving shop. A customer who can't engrave walks in and just describes the seal they keep needing — "I want to do this over and over." The artisan ① recognizes which of 5 standard molds (loop shapes) it is, ② asks what letters to cut (the blanks), ③ cuts them into a proven mold, ④ automatically fits a "misprint detector" (the verifier) and an "out-of-ink stop" (the hardstop), ⑤ pulls one test impression to show the customer, and ⑥ once they approve, hands back a reusable /command they can stamp again any time — the same in Claude Code and in any other agent via a paste-able prompt.

What this tool actually does

Someone who doesn't code can't author a reusable /command that makes an AI repeat a task reliably. loop-forge closes that gap. It takes a vague one-liner and stamps it into a reusable slash command, while automatically attaching the two safety devices a non-developer doesn't even know to ask for:

• Verifier (maker ≠ checker) — the loop's output is re-checked in a pass that is separate from the pass that produced it, so the loop can't grade its own homework.
• Hardstop — a budget/count/cooldown ceiling, so a loop can't quietly break while burning tokens.

That auto-injection is the decisive difference from a plain prompt generator or a developer-facing skill builder.

Before → after (the elevator demo):

User: "I want to summarize 100 shop reviews into 3 lines each"
        │
loop-forge:
  1. Diagnoses → Batch loop
  2. Interviews → where are the items? per-item task? where does output land? a cap?
  3. Auto-injects → verifier (count in == count out + independent spot re-check)
                  + hardstop (max_items budget + per-item fail cap + abort at 20% failure)
  4. Previews → "here's how it will run" (+ optional 1-item sample)
  5. Stamps → /review-summary  (reusable forever; safety baked in)

When it triggers

• /loop or /loop "<one-line situation>" (full command /loop-forge; alias /make-it-loop)
• "automate this" / "make this repeatable" / "turn this into a command"
• "summarize all 100 reviews" / "do this for every item"
• "do X every time an email arrives" / "alert me when a condition is met"
• "generate a few options and pick the best one"
• any time you'd rather capture a recurring task as a reusable /command than re-type the prompt by hand

Triggers are matched on intent, in any language — the same phrasing in Korean, Spanish, Japanese, etc. activates the skill, and the whole interaction then runs in that language (see "Runs in your language" below).

Runs in your language (English asset, multilingual behavior)

Every file in this skill is English — there is no per-language copy. At runtime the orchestrator detects the user's language from their one-liner and conducts the entire interaction in it: the analogy, every interview question, the missing-slot re-asks, the default-value confirmations, and the dry-run preview. The stamped /command's human-readable prose (description, procedure, verifier/hardstop explanations) is written in the user's language, while the structural tokens (frontmatter keys, the archetype id, registry field names, and the ASCII slug name) stay canonical so any teammate's harness can still parse it. This is LLM-driven — there is no translation table.

The 5 loop shapes (everything this tool stamps)

Non-developer work reduces to five shapes. There is no sixth — never invent one (YAGNI). If a request doesn't fit, diagnose the nearest shape or ask one branch question.

6-stage orchestration (the main flow)

Follow the flow exactly; each stage calls a specific asset (lazy-loaded).

Helper-script paths (install-portable): the tools/ and references/ paths below are relative to this skill's own directory. If a relative call can't find a file, resolve it under the skill root — $HOME/.claude/skills/loop-forge/… for install.sh installs, or ${CLAUDE_PLUGIN_ROOT}/skills/loop-forge/… for marketplace (/plugin install) installs. Every helper is optional: if it's still unavailable (or python3 is missing), perform the step yourself from the referenced doc — classify_signals.py is only a hint and check_safety.py only re-checks what Stage 4 already injected, so the flow degrades gracefully without them.

Stage 1 — Entry

• Receive the one-line situation via $ARGUMENTS.
• If it's empty, ask first (in the user's language): "What task do you keep doing by hand? Describe it in one line." (e.g. "I want to summarize 100 shop reviews into 3 lines each.")

Stage 2 — Diagnose the shape

• First-pass hint: run tools/classify_signals.py "<situation>" to get ranked (per-shape signal scores) and ambiguous (a tie flag). This is only a hint — the LLM makes the final call using the semantic signal table in references/classifier.md. The scorer ships an English keyword set; for non-English input it returns no signal, and the LLM classifies from meaning (language-agnostic), so classification never depends on surface keywords.
• If one candidate is clear, name it in plain language ("This is a Batch loop").
• If ambiguous (a top-2 tie) or a known conflict pair, fire the branch question from classifier.md — e.g. "All 100 at once? → Batch. Or each time a new one arrives? → Watch."

Stage 3 — Interview for the blanks

• Pull the confirmed shape's slot questions from references/interviewer.md (each shape has its own set) and ask them with AskUserQuestion, in plain language.
• Apply the missing-slot re-ask rule: if the output location (output_format/final_artifact), the hardstop inputs (max_items/max_iterations/period_limit), or the eval criteria are left as "you decide," re-ask; if still blank, offer conservative defaults explicitly (Batch max 50 · Refine 4 iterations · Watch 20 actions/day, 5-min cooldown).
• For a Watch loop whose triggered action is external (sending/posting), ask "Preview before sending, or approve each one yourself?" to set external_action=true and the gate.
• Two common questions: scope ("Just this project, or usable anywhere?" → project｜global) and name (propose a slug, then confirm; a non-Latin answer is transliterated to an ASCII slug and confirmed).

Stage 4 — Assemble (+ auto-inject safety + static check)

• Use references/assembler.md to substitute the slot values into the shape's skeleton (the {slot} placeholders), producing a neutral loop spec JSON (references/loop-spec-schema.md, 9 fields: name / archetype / label / situation / scope / slots / skeleton / external_action / registry).
• Auto-inject safety: copy the "default verifier" and "default hardstop" text from the chosen archetypes/<shape>.md into registry.verifier / registry.hardstop, and fill registry.trigger / gate / accepted_signal from the shape's mapping. For Watch (or any external_action == true), set the language-independent registry.external_gate to dry_run or human_approval (never none), matching the Stage-3 answer.
• Static gate: run tools/check_safety.py <spec.json>. Exit 2 (missing verifier or hardstop, or a Watch/external loop without an external_gate) → bounce back to Stage 3 to fill the gap. Only exit 0 proceeds. This gate is non-bypassable.

The loop-registry's 5 cells — trigger / gate / verifier / hardstop / accepted_signal — are first-class under registry, so every stamped loop is born registry-shaped. The added external_gate enum is what makes the Watch safety check pass in any language (it gates on the enum, not on prose markers).

Stage 5 — Dry-run preview (the approval gate)

• Follow assembler.md's per-shape dry-run depth: default = a text description ("here's how it will run": skeleton + slots + a summary of the injected safety); Batch/Explore may optionally run a 1-item sample (state the cost); Watch = description only — running a real poll could fire a real send, so never sample it; Pipeline/Refine = description plus, optionally, the first stage or one iteration.
• Show the preview and get explicit approval. No approval, no stamping.

Stage 6 — Stamp (equivalent outputs)

• Primary — Claude Code: render with references/renderers/claude-code.md, then save by scope to <cwd>/.claude/commands/<name>.md (project) or ~/.claude/commands/<name>.md (global). Invoke with /<name> + $ARGUMENTS.
• Optional — Portable Prompt: render with references/renderers/portable-prompt.md into a harness-agnostic, paste-able prompt block (works in any agent — paste the body into the session). This is an opt-in bonus, not required.
• Equivalence contract: the skeleton, verifier, hardstop, and accepted-signal text are byte-identical across both outputs; the only allowed difference is the invocation/variable syntax.
• Finish by telling the user how to run it (Claude Code: /<name> <input>; Portable Prompt: paste the block into your agent).

Never do this (CRITICAL)

• ❌ Never stamp without the Stage-5 approval. Creating the command file is an irreversible artifact — a person sees the preview and says yes first.
• ❌ Never stamp a spec missing a verifier or hardstop. If check_safety.py exits 2, bounce to the interview; never bypass it. Auto-injecting the two safety devices a non-developer doesn't know to ask for is this tool's whole reason to exist.
• ❌ Never stamp a Watch/external action without a dry-run or human-approval gate. A monitor whose action is outbound (sending, posting, hitting a webhook) must carry "preview or human-approve first" — registry.external_gate ∈ {dry_run, human_approval}. It's the most dangerous shape, and the principle is "outbound action = independent gate" (the way email is drafted, then a human sends).
• ❌ Never invent a sixth shape. Reduce everything to Batch / Pipeline / Refine / Watch / Explore (YAGNI). If it doesn't fit, diagnose the nearest shape or ask one branch question.
• ❌ Don't reimplement skill-creator / writing-skills. Those are developer-facing authoring engines. loop-forge is the non-developer layer on top: a plain-language interview + shape diagnosis + safety injection.

Dependent references (lazy load — call per stage)

Disabling

Uninstall or disable the plugin through Claude Code's plugin manager (/plugin), or remove skills/loop-forge from ~/.claude/skills/ and commands/loop-forge.md from ~/.claude/commands/ for a manual install.

Related

• docs/DESIGN.md — the architecture and decision record for this plugin.
• The loop-registry frame (trigger / gate / verifier / hardstop / accepted) — every stamped loop is born matching it, so it's diagnosable at a glance.
• skill-creator / writing-skills — developer-facing authoring engines that loop-forge layers on top of (it is the non-developer layer, not a reinvention).