deepen-plan

deepen-plan is a skill for Claude Code from marchatton/agent-skills. It costs 22 tokens per session (4,221 once invoked), scanned C, original, MIT.

A planning aid that expands an existing software plan with separate research for each major section.

In plain words
What is it for?
Use it to deepen a plan file into a more detailed implementation guide. It requires an existing plan path.
Why use it?
It helps uncover best practices, performance concerns, design considerations, edge cases, and implementation examples before work begins.

Skill for Claude Code

Written for Claude Code: $ARGUMENTS substitution. Also seen: reads .claude/ paths; mentions subagents; installed under .agents/ (shared by several agents).

Good fit Use it to deepen a plan file into a more detailed implementation guide. It requires an existing plan path.

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Install with agentmods
npx agentmods add skills/marchatton/agent-skills/deepen-plan
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.

Any agent
npx skills add marchatton/agent-skills --skill deepen-plan
Clone the repo
git clone --depth 1 https://github.com/marchatton/agent-skills

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for deepen-plan

README.md
[![agentmods](https://agentmods.dev/badge/skills/marchatton/agent-skills/deepen-plan.svg)](https://agentmods.dev/skills/marchatton/agent-skills/deepen-plan)
Your own site
<a href="https://agentmods.dev/skills/marchatton/agent-skills/deepen-plan"><img src="https://agentmods.dev/badge/skills/marchatton/agent-skills/deepen-plan.svg" alt="Measured on agentmods" height="20"></a>
Per session 22 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,221 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00022 $0.04221
Opus 5 $0.00011 $0.02110
Sonnet 5 $0.00004 $0.00844
Haiku 4.5 $0.00002 $0.00422

Measured 8d ago against content hash 00772abfa409, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade C, and why

deepen-plan scanned grade C with 2 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 8d 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.

Reads agent configuration directoriesmediumAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

find ~/.claude/plugins/cache -type d -name "skills" 2>/dev/null

Enumerates other installed skillsmediumAgent snooping

Other skills' SKILL.md files reveal prompts, capabilities and secrets that should be invisible to peers.

ls .claude/skills/
.agents/skills/03-plan/deepen-plan/SKILL.md · 533 lines

How it starts

The opening of the file, as written. The whole thing — 533 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Deepen Plan - Power Enhancement Mode

Introduction

Note: The current year is 2026. Use this when searching for recent documentation and best practices.

This skill takes an existing plan (from wf-shape) and enhances each section with parallel research agents. Each major element gets its own dedicated research sub-agent to find:

  • Best practices and industry patterns
  • Performance optimizations
  • UI/UX improvements (if applicable)
  • Quality enhancements and edge cases
  • Real-world implementation examples

The result is a deeply grounded, production-ready plan with concrete implementation details.

Plan File

Plan path: $ARGUMENTS

If the plan path above is empty:

  1. Check for recent plans: ls -la docs/plans/
  2. Ask the user: "Which plan would you like to deepen? Please provide the path (e.g., docs/plans/2026-01-15-feat-my-feature-plan.md)."

Do not proceed until you have a valid plan file path.

Main Tasks

1. Parse and Analyze Plan Structure

First, read and parse the plan to identify each major section that can be enhanced with research.

Read the plan file and extract:

  • Overview/Problem Statement
  • Proposed Solution sections
  • Technical Approach/Architecture
  • Implementation phases/steps
  • Code examples and file references
  • Acceptance criteria
  • Any UI/UX components mentioned
  • Technologies/frameworks mentioned (Rails, React, Python, TypeScript, etc.)
  • Domain areas (data models, APIs, UI, security, performance, etc.)

Create a section manifest:

Section 1: [Title] - [Brief description of what to research]
Section 2: [Title] - [Brief description of what to research]
...

2. Discover and Apply Available Skills

Dynamically discover all available skills and match them to plan sections. Don't assume what skills exist - discover them at runtime.

Step 1: Discover ALL available skills from ALL sources

# 1. Project-local skills (highest priority - project-specific)
ls .claude/skills/

# 2. User's global skills (~/.claude/)
ls ~/.claude/skills/

# 3. compound-engineering plugin skills
ls ~/.claude/plugins/cache/*/compound-engineering/*/skills/

# 4. ALL other installed plugins - check every plugin for skills
find ~/.claude/plugins/cache -type d -name "skills" 2>/dev/null

# 5. Also check installed_plugins.json for all plugin locations
cat ~/.claude/plugins/installed_plugins.json

Read the full file on GitHub · 533 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. 8d ago First seen · 533 lines · 22 tokens per session scan C 00772abfa409

Subscribe to this mod's changes

deepen-plan is a skill published in the GitHub repository marchatton/agent-skills (5 stars, last pushed 6mo ago), licensed MIT. It adds 22 tokens to every session and 4,221 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it C with 2 findings (reads agent configuration directories, enumerates other installed skills). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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