Agent skill

Plan

Entry point for the three-tier planning system. An agent skill from mattolson/agent-sandbox.

MITAuto-check passedProduct & Project Management

Install Plan

skills CLI

$ npx skills add mattolson/agent-sandbox --skill plan -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install mattolson/agent-sandbox plan --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/mattolson/agent-sandbox.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/plan .claude/skills/plan && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "plan" agent skill from https://github.com/mattolson/agent-sandbox/tree/main/.agents/skills/plan into .claude/skills/plan/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "plan", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/mattolson/agent-sandbox/tree/main/.agents/skills/plan

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add mattolson/agent-sandbox --skill plan -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install mattolson/agent-sandbox plan --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/mattolson/agent-sandbox.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/plan .agents/skills/plan && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "plan" agent skill from https://github.com/mattolson/agent-sandbox/tree/main/.agents/skills/plan into .agents/skills/plan/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "plan", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add mattolson/agent-sandbox --skill plan -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install mattolson/agent-sandbox plan --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/mattolson/agent-sandbox.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/plan .cursor/skills/plan && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "plan" agent skill from https://github.com/mattolson/agent-sandbox/tree/main/.agents/skills/plan into .cursor/skills/plan/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "plan", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/mattolson/agent-sandbox.git --path .agents/skills/plan

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add mattolson/agent-sandbox --skill plan -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install mattolson/agent-sandbox plan --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/mattolson/agent-sandbox.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/plan .gemini/skills/plan && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "plan" agent skill from https://github.com/mattolson/agent-sandbox/tree/main/.agents/skills/plan into .gemini/skills/plan/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "plan", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install mattolson/agent-sandbox plan

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add mattolson/agent-sandbox --skill plan -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/mattolson/agent-sandbox.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/plan .github/skills/plan && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "plan" agent skill from https://github.com/mattolson/agent-sandbox/tree/main/.agents/skills/plan into .github/skills/plan/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "plan", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add mattolson/agent-sandbox --skill plan -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install mattolson/agent-sandbox plan --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/mattolson/agent-sandbox.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/plan .opencode/skills/plan && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "plan" agent skill from https://github.com/mattolson/agent-sandbox/tree/main/.agents/skills/plan into .opencode/skills/plan/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "plan", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: plan
GitHub stars: 208
Token cost: ~1.1k tokens
SKILL.md length: 416 words
Files: 1
Skills in repo: 6
Repo updated: Oct 1, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Entry point for the three-tier planning system. An agent skill from mattolson/agent-sandbox.

Works in 2 steps: Update the affected plan document… → Create a decision record documenting the…
Starting planning work at any level - project
SKILL.md covers The Three Tiers, Naming Convention, File Structure and Learnings and Decisions, plus 2 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Plan is an agent skill from mattolson/agent-sandbox. Entry point for the three-tier planning system. Use when starting planning work at any level - project, milestone, or task.

Its SKILL.md is about 1.1k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Product & Project Management, covering Project management. The repository describes itself as: Secure local dev environment for collaboration with AI coding agents. The licence is MIT.

When your agent uses it

Starting planning work at any level - project
Tasks that involve Project management

Example prompts

“/plan”

Workflow steps

2 steps, taken from the first numbered list in SKILL.md.

Update the affected plan document (project.md, milestone.md) to reflect current state
Create a decision record documenting the change and rationale

What it can do on your machine

Read from SKILL.md and the folder at commit c5b65e7. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are markdown).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Plan loads about 1.1k tokens when it runs. Until then it costs about 32 tokens; SKILL.md has 416 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~32
When it runs · the whole SKILL.md, loaded when a task matches: ~1.1k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from mattolson/agent-sandbox at commit c5b65e7, republished under its MIT licence (© mattolson). 416 words, ~1,102 tokens.

Download SKILL.mdSave it as .claude/skills/plan/SKILL.md (or your agent's skills folder).

name: plan
description: Entry point for the three-tier planning system. Use when starting planning work at any level - project, milestone, or task.

Planning System

This is a three-tier planning system for iterative project development. Each tier produces artifacts that inform the next.

The Three Tiers

Tier 1: Project Planning

High-level planning done once at project start. Defines goals, approach, architecture, and milestones.

Output: docs/plan/project.md
Produces: List of milestones with identifiers (e.g., m1-auth, m2-dashboard)

Tier 2: Milestone Planning

Done at the start of each milestone. Breaks the milestone into discrete tasks.

Input: Project plan
Output: docs/plan/milestones/{milestone}/milestone.md
Produces: List of tasks with identifiers (e.g., m1.1-login-form, m1.2-signup-flow)

Tier 3: Task Planning

Done at the start of each task. Plans implementation, tracks execution, captures learnings.

Input: Milestone plan + accumulated learnings
Output: docs/plan/milestones/{milestone}/tasks/{task}/task.md
Also appends to: docs/plan/learnings.md

Naming Convention

Milestones: m{number}-{name} (e.g., m1-auth, m2-dashboard)
Tasks: m{milestone}.{task}-{name} (e.g., m1.1-login-form, m1.2-signup-flow)

File Structure

docs/plan/
├── project.md              # Tier 1 output - goals, architecture, milestones
├── learnings.md            # Accumulated learnings from all tasks
├── decisions/
│   ├── 001-switch-to-graphql.md
│   └── 002-defer-analytics.md
└── milestones/
    ├── m1-auth/
    │   ├── milestone.md    # Tier 2 output - milestone plan and task list
    │   ├── {milestone-level artifacts}
    │   └── tasks/
    │       ├── m1.1-login-form/
    │       │   ├── task.md
    │       │   └── {task artifacts}
    │       └── m1.2-signup-flow/
    │           └── task.md
    └── m2-dashboard/
        ├── milestone.md
        └── tasks/
            └── m2.1-user-profile/
                └── task.md

Learnings and Decisions

Planning is imperfect. As work progresses, we discover things we didn't anticipate and make decisions that change the plan.

Learnings

Lessons learned during execution that inform future planning. Captured in docs/plan/learnings.md. These may be technical or process-related.

Technical examples:

"API rate limits are lower than documented, need to batch requests"
"Integration tests take 5 minutes, run selectively during development"
"The auth library doesn't support refresh tokens out of the box"

Process examples:

"Breaking tasks into half-day chunks improved estimation accuracy"
"Spiking unfamiliar APIs before planning saved rework"
"Pairing on complex integrations caught issues earlier"

Learnings are reviewed at the start of each planning session.

Show full SKILL.md (185 more words)Show less

Decisions

Significant changes to the plan, recorded as individual documents in docs/plan/decisions/.

When a decision changes the plan:

Update the affected plan document (project.md, milestone.md) to reflect current state
Create a decision record documenting the change and rationale

Decision document format:

markdown

# {Number}: {Title}

## Status

{Proposed | Accepted | Superseded by XXX}

## Context

{What situation prompted this decision?}

## Decision

{What are we changing?}

## Rationale

{Why this approach over alternatives?}

## Consequences

{What changes as a result? What are the tradeoffs?}

Decisions are numbered sequentially: 001-switch-to-graphql.md, 002-defer-analytics.md.

Workflow

This is a conversational process. Describe your intent and I will:

Identify which planning tier applies
Look up relevant identifiers from existing plans
Guide you through the appropriate planning process

Examples:

"Let's plan a new project" → Tier 1 project planning
"Let's start the auth milestone" → I look up the milestone in project.md, begin tier 2 planning
"Ready to work on login" → I find the task in the milestone plan, begin tier 3 planning

Learnings from each completed task feed into future task planning. When discoveries require plan changes, we update the plan and record a decision.

Getting Started

Describe what you want to work on:

Starting a new initiative? We'll do project planning.
Ready to begin a milestone? Tell me which one.
Ready to implement a task? Tell me what you're building.

Files

Just SKILL.md in .agents/skills/plan of mattolson/agent-sandbox.

Open the folder on GitHubat commit c5b65e7

Compare with similar skills

Plan next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Plan compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Plan this skillmattolson/agent-sandbox	208	—	~1.1k	Automated safety check: Pass	MIT	6 days ago
CCPM Project Managementautomazeio/ccpm	8.4k	—	~1.1k	Automated safety check: Pass	MIT	6 mo ago
Uvastral-sh/claude-code-plugins	314	2 repos	~980	Automated safety check: Pass	Apache-2.0	7 mo ago
Project Managementkunchenguid/firstmate	7.6k	—	~2.1k	Automated safety check: Pass	MIT	today
Hivemind Goalsactiveloopai/hivemind	1.6k	—	~1.7k	Automated safety check: Notes	Apache-2.0	9 days ago
Ichartjswanghetommy/ichartjs	352	—	~3.4k	Automated safety check: Pass	Apache-2.0	yesterday

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Questions about Plan

What does Plan do?

Entry point for the three-tier planning system. An agent skill from mattolson/agent-sandbox. Plan is an agent skill from mattolson/agent-sandbox. Entry point for the three-tier planning system.

When should I use Plan?

Plan fits situations like: starting planning work at any level - project; tasks that involve Project management.

How do I install Plan in Claude Code?

Run `npx skills add mattolson/agent-sandbox --skill plan -a claude-code`. Or copy the skill folder (.agents/skills/plan in mattolson/agent-sandbox) into .claude/skills/plan in your project. Claude Code loads it when a task matches its description.

How do I install Plan in Codex?

Run `npx skills add mattolson/agent-sandbox --skill plan -a codex`. Or copy the skill folder (.agents/skills/plan in mattolson/agent-sandbox) into .agents/skills/plan in your project. Codex loads it when a task matches its description.

Can I use Plan in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add mattolson/agent-sandbox --skill plan -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/plan, .gemini/skills/plan, .github/skills/plan and .opencode/skills/plan in your project.

What does Plan need to run?

SKILL.md names no scripts, command-line tools or credentials: Plan is instructions for the agent only.

Does Plan access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Plan safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Plan use?

Plan is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Plan use?

About 1.1k tokens (SKILL.md is roughly 4.4k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Plan?

Skills that share tags, products or a category with Plan: CCPM Project Management (automazeio/ccpm, 8.4k stars), Uv (astral-sh/claude-code-plugins, 314 stars), Project Management (kunchenguid/firstmate, 7.6k stars) and Hivemind Goals (activeloopai/hivemind, 1.6k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Plan?

mattolson (a GitHub user) maintains it in mattolson/agent-sandbox, which has 208 GitHub stars. The repository holds 6 skills in this directory. The repository was last updated on October 1, 2026.

Source: mattolson/agent-sandbox on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Plan

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Planning System

The Three Tiers

Tier 1: Project Planning

Tier 2: Milestone Planning

Tier 3: Task Planning

Naming Convention

File Structure

Learnings and Decisions

Learnings

Decisions

Workflow

Getting Started

Files

Compare with similar skills

Similar skills

More from mattolson/agent-sandbox

Related

Questions about Plan