Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/archive228/loopkit/planner-spec-expandnpx skills add Archive228/loopkit --skill planner-spec-expandgit clone --depth 1 https://github.com/Archive228/loopkitWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00031 | $0.00888 |
| Opus 5 | $0.00015 | $0.00444 |
| Sonnet 5 | $0.00006 | $0.00178 |
| Haiku 4.5 | $0.00003 | $0.00089 |
Grade A, and why
planner-spec-expand scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 49 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Planner Spec Expand
A one-line brief ("build a claude.ai clone", "a habit tracker with streaks") is not enough surface for a coding agent to make good decisions from. It has no design language, no acceptance criteria, no ordering. The generator ends up inventing scope mid-session and shipping incoherent slices.
The planner's job is to expand the brief into a spec dense enough that every downstream decision — what feature to pick, what "done" looks like, what the button should say — has an answer already written down. See Prithvi's post on planner/generator/evaluator separation for the underlying architecture: https://www.prithvirajrk.com/blog/three-agent-harness.
When to apply
- The user handed you a brief under ~200 words and expects a real product.
- You're about to seed [[feature-list-json]] and the brief has no orderable features yet.
- Scope drifted mid-project and the original spec no longer describes the target — rewrite, don't patch.
Procedure — expand in this order
Do the sections in order. Later sections depend on earlier ones being locked.
- Restate the brief in one paragraph. In your own words, what is being built and for whom. If you can't write this cleanly, ask the user before continuing — the brief is under-specified.
- Pick a design language. One sentence each on: visual tone (minimal / dense / playful), typography stance (one sans / serif+sans / mono accents), color posture (monochrome + one accent / two-color / full palette), density (airy / compact). This locks a thousand later micro-decisions.
- Enumerate the acceptance surface. For each user-observable capability, write one sentence of user-observable behavior AND the concrete steps a human would take to verify it. This is the shape [[feature-list-json]] wants — write it in that shape now.
- Order the features. Sort by dependency: nothing appears before what it depends on. Ties broken by "what does the user see first when they open the app." The top of the list must be runnable-alone.
- Name the out-of-scope. One short list of things the brief could imply but you are explicitly not building. Prevents the generator from wandering.
- Write the smoke path. The single user journey that proves the product exists — 3-6 steps end-to-end. This becomes the initializer's smoke test.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 49 lines · 31 tokens per session scan A e8636192cf8c
planner-spec-expand is a skill published in the GitHub repository Archive228/loopkit (753 stars, last pushed 1mo ago), licensed MIT. It adds 31 tokens to every session and 888 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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