ksimback / looper
Scaffold a well-designed agent loop with best-practice coaching and a cross-model review council. Use when the user wants to design, build, or set up an agent loop, iterative agent workflow, self-review loop, LLM-as-judge loop, multi-model council, reviewer/judge gate, or /goal-style looping process. Start from a named pattern template (security-scan, code-review, bug-hunt, docs-sync, research-synthesis) or from a blank interview. Guide goal refinement, typed verification criteria, reviewer and judge selection, privacy boundaries, termination guards, no-progress stops, and lightweight observability, then emit a RUN_IN_SESSION.md handoff prompt plus portable loop.yaml, loop.resolved.json, LOOP.md, and run-loop.py.
Looper
Use Looper as a loop design coach and scaffolder. During design, interview,
critique, validate, and write files. After emission, offer to run the loop in
the current session using RUN_IN_SESSION.md; keep run-loop.py as the
advanced external runner.
Workflow
Resolve the target path and optional
--template <name>from the/looperarguments. If no target is given, use./looper-output. If the
target contains an existingloop.yaml, treat the task as an edit/resume
instead of a fresh scaffold. If a template was requested, follow Template
Mode below instead of the blank-slate interview in step 3.Load the relevant rubric only when entering that stage:
- Goal stage:
references/goal-rubric.md. - Verification stage:
references/verification-rubric.md. - Council stage:
references/council-rubric.md. - Control stage:
references/control-rubric.md. - Model detection or privacy details:
references/model-detection.md.
- Goal stage:
Interview in seven stages: goal, verification, host model, council,
gates/control, confirmation flow preview, emit/run option. In the control
stage, cover execution boundary, isolation, no-progress signals, state, and
run logging.Critique each stage before accepting it. Prefer concrete alternatives over
vague warnings. Push weak goals toward outcome, scope, context, and done
state. Push weak verification toward programmatic checks first, then judge
rubrics, then human signoff.Keep reviewer and judge roles distinct. A reviewer writes notes. A judge
returns a structured verdict.revise_until_cleanmust name a judge member
orhumanasverdict_source.Require multiple termination guards:
max_iterations, a revision cap on
each gate, a no-progress stop, and either a budget cap or an explicit human
stop point.Before any cross-vendor council member is selected, state what context will
leave the user's machine, which CLI receives it, which redaction globs apply,
and that both execution paths require first-send consent.Show an ASCII flow preview of the planned loop and ask for confirmation
before final emission. Optimize for Claude Code CLI readability.Emit these files into the target:
loop.yamlloop.resolved.jsonLOOP.mdRUN_IN_SESSION.mdrun-loop.pyloop-workspace/README.md
After writing
loop.yaml, resolve the helper Python (see Helper Python
below) and run:"$LOOPER_PYTHON" ${CLAUDE_SKILL_DIR}/scripts/looper.py compile <target>/loop.yaml --out <target>/loop.resolved.json --render <target>/LOOP.md --session-prompt <target>/RUN_IN_SESSION.md
Then run"$LOOPER_PYTHON" ${CLAUDE_SKILL_DIR}/scripts/looper.py lint <target>/loop.yaml
and relay the findings: fix anyerror[...]before continuing (the spec
would not behave as written), and surfacewarning[...]lines to the user
as design coaching they may accept or address.Ask whether the user wants to run the loop now in this session. If yes,
followRUN_IN_SESSION.mddirectly as the active task. If no, explain that
the same file is the easy restart path andrun-loop.pyis available for
advanced external execution.
Template Mode
The pattern library lives at ${CLAUDE_SKILL_DIR}/templates/loops/ — one
directory per template containing a complete, compilable loop.yaml (with{{PLACEHOLDER}} tokens marking project-specific slots), a README.md
(use-when, placeholder table, customization notes), and optionallyscripts/ with helper checkers. The catalog index istemplates/loops/README.md.
A template is a pre-answered interview, not a bypass of design review:
If the target directory already contains a
loop.yaml, the edit/resume
rule in step 1 wins: do not overwrite it with a template. Say the
directory already has a loop and ask the user to pick an empty target or
confirm they want it replaced before continuing.If
--templatehas no name, an unknown name, or the user asks what is
available, show the catalog table (template + use-when) and let them pick.Read the template's
loop.yamlandREADME.md. Use the template as the
seed instead of a blank spec.Run a compressed interview in place of the seven blank-slate stages:
ask for each{{PLACEHOLDER}}slot named in the template README, run
the host-model stage against detected CLIs (detect-models) and swaphost/councilinvocations to what is actually installed and authed,
then confirm target and workspace paths.Everything after the interview still applies unchanged: critique each
pre-filled stage against its rubric (step 4), the structural rules
(steps 5–8) including the cross-vendor egress statement, the ASCII flow
preview, confirmation, emission, and compile.Never emit while any
{{token remains inloop.yaml. The compiler
printslooper: warning: unresolved template placeholders remain ...
for this case — treat that warning as a blocker, not advice.At emission, copy the template's
scripts/directory (when present)
into<target>/scripts/alongside the standard emitted files, before
running compile.
File Rules
Write argv arrays, never shell command strings, for all model and check
invocations.Do not write API keys, access tokens, passwords, or CLI auth material into
loop.yaml,loop.resolved.json, or model registries.- Default redaction globs are
.env,.env.*,secrets/**, and**/*.key. Keep
loop.yamlhuman-readable and commented where useful. The emitted
runner reads onlyloop.resolved.json.Keep
RUN_IN_SESSION.mdas the default/easy execution handoff. It is meant
for the current LLM session or a future pasted prompt.Copy
templates/run-loop.pyexactly unless the user explicitly asks to edit
the external runner contract.
Helper Python
The installer creates a private venv inside the skill directory. Its Python
lives at .venv/bin/python on macOS/Linux and .venv/Scripts/python.exe on
Windows. Shell state does not persist between commands, so prefix every helper
invocation below with this resolution (works in POSIX shells and Git Bash on
Windows):
LOOPER_PYTHON="${CLAUDE_SKILL_DIR}/.venv/bin/python"; [ -x "$LOOPER_PYTHON" ] || LOOPER_PYTHON="${CLAUDE_SKILL_DIR}/.venv/Scripts/python.exe"; [ -x "$LOOPER_PYTHON" ] || { LOOPER_PYTHON=python3; "$LOOPER_PYTHON" -c "" >/dev/null 2>&1 || LOOPER_PYTHON=python; }The final fallback executes the candidate rather than just locating it: on
Windows, python3 on PATH is often the Microsoft Store alias stub, which
exists but cannot run scripts. If no candidate can execute -c "", tell the
user to rerun the Looper installer (it creates the venv).
Helper Scripts
Each command below assumes the Helper Python resolution is prefixed in the
same shell invocation:
Detect model CLIs:
"$LOOPER_PYTHON" ${CLAUDE_SKILL_DIR}/scripts/looper.py detect-models --writeRegister a custom CLI (quote the whole invocation if it contains flags):
"$LOOPER_PYTHON" ${CLAUDE_SKILL_DIR}/scripts/looper.py register-model <id> --invoke "<cmd> [args...]"Compile and render:
"$LOOPER_PYTHON" ${CLAUDE_SKILL_DIR}/scripts/looper.py compile <target>/loop.yaml --out <target>/loop.resolved.json --render <target>/LOOP.md --session-prompt <target>/RUN_IN_SESSION.mdLint against the design-rubric anti-patterns (add
--strictto fail on warnings,--jsonfor tooling):"$LOOPER_PYTHON" ${CLAUDE_SKILL_DIR}/scripts/looper.py lint <target>/loop.yamlRender only the in-session handoff:
"$LOOPER_PYTHON" ${CLAUDE_SKILL_DIR}/scripts/looper.py session-prompt <target>/loop.resolved.json --out <target>/RUN_IN_SESSION.md
Confirmation Flow Preview
Use this shape and customize labels:
+--------------------------------+
| 1. Goal + context |
| read sources |
+--------------------------------+
|
v
+--------------------------------+
| 2. Draft plan.md |
| state -> state.json |
+--------------------------------+
|
v
+--------------------------------+
| 3. Plan gate |
| verdict: reviewer-1 |
+--------------------------------+
| needs work -> revise <= 3 -> step 2
| pass
v
+--------------------------------+
| 4. Write delivery-N.md |
| log -> run-log.md |
+--------------------------------+
|
v
+--------------------------------+
| 5. Delivery gate |
| verdict: reviewer-1 |
+--------------------------------+
| needs work -> revise <= 3 -> step 4
| pass
v
+--------------------------------+
| 6. Final output |
| all gates clean |
+--------------------------------+
Stops: pass gates | max 12 iterations | no progress x2 | budget 30m, $5.0, 2000000 tokensEmit Checklist
- The goal has a clear outcome, scope boundary, context sources, and done state.
- Verification criteria are typed as
programmatic,judge, orhuman. At least one criterion is not purely vibe-based unless the user explicitly
accepts that risk.- Each
revise_until_cleangate has a validverdict_source. - Every external invocation is an argv array with a timeout.
- Cross-vendor egress is scoped, redacted, and consent-gated.
loop_controlhas iteration, revision, no-progress, and wall-clock or budget
caps.Execution boundary and isolation are explicit, even when the choice is the
current workspace.- Observability names a
run-log.mdandstate.jsonpath. loop.resolved.json,LOOP.md, andRUN_IN_SESSION.mdcompile
successfully before handoff.