Subagent

Planner by microsoft

Read-only planning specialist that analyzes requirements, explores the codebase, and creates detailed implementation plans before coding begins

Type: Subagent
Repository: microsoft/skills
GitHub stars: 3.1k
License: MIT
Repo last updated: Sep 24, 2026
Source file: .github/agents/planner.agent.md

What Planner by microsoft is

Planner by microsoft is a subagent published in the microsoft/skills repository on GitHub, which has about 3.1k stars. The repository describes itself as: “Skills, MCP servers, Custom Agents, Agents.md for SDKs to ground Coding Agents”

A subagent is a specialist assistant that Claude can hand part of a task to. It is a markdown file whose frontmatter sets a name, a description that tells Claude when to delegate, and optionally the tools and model it may use; the body becomes the subagent's own system prompt.

Because a subagent works in its own context, it keeps the main conversation focused: Claude can send a narrow job, such as a review or a specialised analysis, to Planner and get back a compact result.

It is set up to use these tools: read, search, web. Limiting tools is a good sign: the subagent can only do what those tools allow.

How to install Planner by microsoft

Claude Code

Download planner.agent.md from the repository.
Save it to ~/.claude/agents/ to use it in every project, or to .claude/agents/ inside one project to share it through version control.
Claude Code watches these folders, so the subagent is usually available right away. Ask Claude to use it by name, or @-mention it to make sure it runs.

Claude Cowork

Cowork loads subagents through plugins. If the repository is packaged as a plugin marketplace, add it under Customize → Plugins → Add marketplace and install the plugin that contains this subagent.
Otherwise, bundle the file into your own plugin's agents/ folder and upload it from Customize → Plugins.

New to extending Cowork? Our plugins guide and Customize guide explain how skills, plugins, and connectors fit together.

Inside the source file

An excerpt from .github/agents/planner.agent.md, shared under the repository's MIT license. Read the full file on GitHub.

You are a Planning Specialist for the CoreAI DIY project. Your role is to analyze requirements, explore the codebase, and create detailed implementation plans without making any code changes.

Your Responsibilities

Understand Requirements

Clarify ambiguous requests with the user
Reference PRD (docs/PRD.md) for feature context
Identify affected components and workflows

Explore the Codebase

Search for relevant files and patterns
Read existing implementations to understand conventions
Identify dependencies and integration points

Create Implementation Plans

Break down work into discrete, testable tasks
Specify which files need changes
Include code patterns from existing implementations
Estimate complexity and potential risks

Validate Feasibility

Check for conflicts with existing code
Identify breaking changes
Note any dependencies that need to be added

Planning Template

For each implementation plan, structure your response as:

Summary

Brief description of what will be built

Files to Create/Modify

path/to/file.ts - Description of changes

Implementation Steps

Step with specific details
Step with code patterns to follow

Dependencies

Any new packages needed
Any breaking changes

Testing Strategy

What tests to add/modify

Risks & Considerations

Potential issues to watch for

Key References

Types: src/frontend/src/types/index.ts
App Store: src/frontend/src/store/app-store.ts
Node Components: src/frontend/src/components/nodes/
API Routers: src/backend/app/routers/
Pydantic Models: src/backend/app/models/
PRD: docs/PRD.md

Conventions to Reference

When planning, ensure adherence to:

Component pattern: memo() + named function
Zustand with subscribeWithSelector
Multi-model Pydantic pattern (Base → Create → Update → Response)
Design tokens for styling (--frontier-, --foundry-)

Handoff

Once your plan is complete and approved, hand off to the appropriate specialist agent for implementation:

Frontend Agent: React/TypeScript changes
Backend Agent: FastAPI/Python changes
Infrastructure Agent: Azure/Bicep changes

Before you install

Read the whole file first. Skills, commands, and subagents are instructions Claude will follow, so make sure they match what you want.
Check which tools, scripts, or MCP servers it uses. Local servers and scripts run with your permissions.
Try it in a test project or a copy of your files before pointing it at real work.
Pin the version you tested, and review changes before updating.
Watch for instructions that fetch web content or run shell commands; those are where prompt injection risks start. See our prompt injection guide.

FAQ

What is Planner by microsoft?

Planner by microsoft is a subagent for Claude Code and Claude Cowork from the microsoft/skills repository on GitHub. Read-only planning specialist that analyzes requirements, explores the codebase, and creates detailed implementation plans before coding begins

How do I install Planner by microsoft in Claude Code?

Download planner.agent.md from the repository. Save it to ~/.claude/agents/ to use it in every project, or to .claude/agents/ inside one project to share it through version control. Claude Code watches these folders, so the subagent is usually available right away. Ask Claude to use it by name, or @-mention it to make sure it runs.

Can I use Planner by microsoft in Claude Cowork?

Cowork loads subagents through plugins. If the repository is packaged as a plugin marketplace, add it under Customize → Plugins → Add marketplace and install the plugin that contains this subagent. Otherwise, bundle the file into your own plugin's agents/ folder and upload it from Customize → Plugins.

Is Planner by microsoft safe to install?

It is a third-party community resource, not reviewed by Anthropic or this site. Read the source file first, check which tools and connectors it uses, and install only from sources you trust.

Similar resources

Browse all skills, subagents, and plugins →

Listing data comes from the public GitHub repository and was last checked in September 2026. Excerpts are © their authors and shared under MIT. This directory is independent and not affiliated with Anthropic or the resource's authors.