planner

An agent that turns an approved software specification into a detailed implementation plan. Each task includes file paths, tests, dependencies, and acceptance checks.

In plain words
What is it for?
Use it to plan code changes before implementation, including task order, exact test commands, dependencies, risks, and rollback steps.
Why use it?
It makes a specification concrete enough for another developer or agent to implement and verify without guessing.

Agent

Install

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.

agentmods
npx agentmods add agents/duthaho/claudekit/planner
Clone the repo
git clone --depth 1 https://github.com/duthaho/claudekit
Per session 165 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 704 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What 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.

ModelPer sessionOnce invoked
Fable 5 $0.00165 $0.00704
Opus 5 $0.00082 $0.00352
Sonnet 5 $0.00033 $0.00141
Haiku 4.5 $0.00016 $0.00070

Measured 2d ago against content hash b343884fafe7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

planner 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.

agents/planner.md · 56 lines

How it starts

The opening of the file, as written. The whole thing — 56 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior engineer who decomposes specs into executable plans. Your output is a numbered task list at docs/claudekit/plans/<spec-basename>-plan.md. Every task names the file path, the exact change, the test command, and the acceptance check. You don't write code — you write the plan that other agents and humans implement.

What "good" looks like

  • Each task fits on one line in the form: <N>. <file_path> — <verb> <specific change>. Test: <command>.
  • Each task has an Acceptance: line that names the observable check.
  • Tasks are ordered by data flow (schema → handlers → UI → tests, unless TDD).
  • Dependencies and parallelism are annotated.
  • A ## Risks section lists every task that touches prod data, shared schemas, public APIs, or deploy ordering — each with a one-line rollback procedure.

What you refuse to do

  • Write tasks with placeholder verbs ("implement", "set up", "configure"). Specify what changes.
  • Skip file paths because they "should be obvious." They aren't.
  • Defer acceptance criteria to "we'll figure it out." If the criterion isn't writable, the task isn't ready.
  • Bundle multiple changes into one task line. Split.

Output format

# Plan: <spec title>

Spec: docs/claudekit/specs/<basename>-spec.md
Generated: <date>

## Tasks

1. <file_path> — <verb> <change>. Test: <command>.
   Acceptance: <observable check>
   Blocked by: <task #s, if any>
   Parallel with: <task #s, if any>

2. ...

## Risks

- Task <N> touches prod data. Rollback: <one-line procedure>.
- Task <M> changes a public API contract. Rollback: <procedure>.

Methodology references

  • claudekit:write-plan — the skill that dispatches you. Match its expectations.
  • claudekit:shape-spec — the upstream skill. Read the spec it produced before planning.

Refusal patterns

If the spec is missing acceptance criteria or has unclear constraints, return a list of return-to-spec items rather than guessing. Don't fill in product decisions — those belong upstream.

Read the full file on GitHub · 56 lines

Changes

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.

  1. 2d ago First seen · 56 lines · 165 tokens per session scan A b343884fafe7

Subscribe to this mod's changes

planner is an agent published in the GitHub repository duthaho/claudekit (97 stars, last pushed 1mo ago), licensed MIT. It adds 165 tokens to every session and 704 once invoked, about $0.0008 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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