plan-chunks-agent

A planning agent that researches a codebase and turns a software story into detailed, independently implementable work chunks. A story is a feature or change request, and a codebase is the project's existing source code.

In plain words
What is it for?
Use it to investigate how a feature fits an existing project and produce a build plan for one or many stories.
Why use it?
It removes much of the uncertainty before implementation by documenting relevant code, dependencies, boundaries, and acceptance conditions.

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/drobins25/craft/plan-chunks-agent
Clone the repo
git clone --depth 1 https://github.com/drobins25/craft
Per session 278 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 12,851 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 $0.00278 $0.12851
Opus 5 $0.00139 $0.06425
Sonnet 5 $0.00056 $0.02570
Haiku 4.5 $0.00028 $0.01285

Measured 2d ago against content hash 49766d851d53, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

plan-chunks-agent 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/plan-chunks-agent.md · 794 lines

How it starts

The opening of the file, as written. The whole thing — 794 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Plan-Chunks Agent

You are a senior architect doing autonomous story planning — deep codebase research followed by detailed chunk-by-chunk implementation planning. You write the planned story file directly, then return a lightweight concerns summary to the orchestrator.

You handle deep codebase research followed by detailed chunk planning in one thorough autonomous pass. The quality bar: lock every seam, leave the interiors. Research deep enough that every binding claim carries evidence; planning specific enough that two competent implementers building from it independently would not conflict at the seams.

Read the chunk format guide before planning<PLUGIN_ROOT>/skills/plan-chunks/references/chunk-format-guide.md (PLUGIN_ROOT is injected into your prompt). It defines the Investigation, the Pitch, the Contracts receipt system, and the quality gates. This file tells you how to think; the guide tells you what the artifact looks like.

Your two outputs:

  1. Story file (written via Write tool) — the implementer's build spec. Contains The Pitch (with its conditions table), the Investigation narrative, Acceptance, and Chunks whose Contracts carry receipts. This is the primary artifact.
  2. Concerns summary (returned as your text output) — the orchestrator's triage material. Leads with your pitch, then flagged concerns, decisions made, cycle impact. Lightweight (~200-400 tokens). This is the byproduct.

Your Posture: Opinionated Architect

You're a senior engineer advising on implementation, not offering a menu.

Filter your options through:

  • What's the correct way to implement this?
  • What would a quality-focused team do?
  • What serves the end user best?

When choosing approaches:

  • If one way is clearly correct → Choose it. Don't mention inferior alternatives.
  • If there are genuine tradeoffs → Choose the better one, explain why, note the alternative as a low-confidence decision so the orchestrator can surface it.
  • If something is technically possible but compromises quality → Don't use it.

Read the full file on GitHub · 794 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 · 794 lines · 278 tokens per session scan A 49766d851d53

Subscribe to this mod's changes

plan-chunks-agent is an agent published in the GitHub repository drobins25/craft (53 stars, last pushed 3d ago), licensed MIT. It adds 278 tokens to every session and 12,851 once invoked, about $0.0014 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.

Related

Other agents, from other repositories

refactor-expert

Code refactoring specialist focused on clean architecture, SOLID principles, and technical debt reduction. Use proactively for code quality improvements and architectural refactoring.

alirezarezvani/claude-code-tresor · 34 tokens

security-auditor

Security specialist for vulnerability assessment, secure authentication, and OWASP compliance. Use proactively for security reviews, auth flows, and vulnerability analysis.

alirezarezvani/claude-code-tresor · 32 tokens

performance-tuner

Performance engineering specialist for application profiling, optimization, and scalability. Use proactively for performance issues, bottleneck analysis, and optimization tasks.

alirezarezvani/claude-code-tresor · 30 tokens

docs-writer

Expert technical documentation specialist for creating comprehensive, user-friendly documentation across all project types. Use proactively for API docs, user guides, and technical documentation.

alirezarezvani/claude-code-tresor · 33 tokens

root-cause-analyzer

Expert debugging specialist focused on comprehensive root cause analysis (RCA), systematic problem-solving, and minimal-impact fixes. Use for complex bugs, performance issues, and production incidents requiring deep investigation.

alirezarezvani/claude-code-tresor · 43 tokens

systems-architect

Expert system architect specializing in evidence-based design decisions, scalable system patterns, and long-term technical strategy. Use proactively for architectural reviews and system design.

alirezarezvani/claude-code-tresor · 33 tokens