greybeard 0.3.3

CLI-first Staff Review & Decision Assistant

🧙 greybeard

        .  .
       .|  |.
       ||  ||
      .+====+.
      | .''. |
      |/ () \|    "Would I be okay getting paged
     (_`.__.'_)    about this at 3am six months
     //|    |\\    from now?"
    || |    | ||
    `--'    '--`
   ~~~~~~~~~~~~~~~~~

A CLI-first thinking tool that channels the calm, battle-tested wisdom of a Staff / Principal engineer — helping you review decisions, systems, and tradeoffs before you ship them.

The greybeard has been paged at 3am. They've watched confident decisions become production incidents. They've seen "we'll clean it up later" last five years. They're not here to block you — they're here to make sure you've thought it through.

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Philosophy

This is not a linter. It won't yell at your variable names or enforce opinionated formatting.

This is a thinking partner. It models how Staff and Principal engineers reason about systems: failure modes, ownership, long-term cost, and the human impact of decisions. It asks the uncomfortable questions so your reviewer doesn't have to.

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What It Does

• Sanity-checks architecture decisions and design docs
• Surfaces operational risks, ownership gaps, and maintenance burden
• Coaches you on how to communicate decisions to peers, teams, and leadership
• Teaches Staff-level reasoning through mentorship mode
• Reviews your own thinking before you share it with others
• Integrates into Claude Desktop, Cursor, Zed and any MCP-compatible tool

📚 Full Documentation — Installation, configuration, guides, and reference

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Quick Start

Install from PyPI

# Using uv (recommended - faster)
uv pip install greybeard

# Or using pip
pip install greybeard

With optional extras:

uv pip install "greybeard[anthropic]"     # Add Claude/Anthropic support
uv pip install "greybeard[all]"           # Everything

# Or with pip
pip install "greybeard[anthropic]"
pip install "greybeard[all]"

Then configure:

greybeard init          # interactive setup wizard
greybeard packs         # see available content packs

Development installation

For contributing or local development:

Development installation

For contributing or local development:

git clone https://github.com/btotharye/greybeard.git
cd greybeard

# Option 1: Use Makefile (easiest)
make install-dev
make test
make help                      # see all available commands

# Option 2: Use uv directly
uv pip install -e ".[dev]"
uv run pytest

# Option 3: Traditional pip
pip install -e ".[dev]"
pytest

See CONTRIBUTING.md for detailed development setup.

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LLM Backends

greybeard works with whatever LLM you prefer — cloud or local. Configure once with greybeard init or greybeard config set.

Backend	How	What you need
openai	OpenAI API	OPENAI_API_KEY
anthropic	Anthropic API	ANTHROPIC_API_KEY + greybeard[anthropic] extra (see Quick Start)
ollama	Local (free)	Ollama running: ollama serve
lmstudio	Local (free)	LM Studio server running

# Configure interactively
greybeard init

# Or set directly
greybeard config set llm.backend ollama
greybeard config set llm.model llama3.2

greybeard config set llm.backend openai
greybeard config set llm.model gpt-4o-mini

greybeard config show

Config lives at ~/.greybeard/config.yaml.

See LLM Backends Guide for detailed setup instructions.

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Modes

Mode	Description
review	Concise Staff-level review of a decision or diff
mentor	Explain the reasoning and thought process behind concerns
coach	Help phrase constructive feedback for a specific audience
self-check	Review your own decision before sharing it

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Usage

# Review a git diff (default mode + default pack from config)
git diff main | greybeard analyze

# Review with a specific mode and pack
git diff main | greybeard analyze --mode mentor --pack oncall-future-you

# Review a design doc and save the output
cat design-doc.md | greybeard analyze --output review-2024-03-01.md

# Self-check a decision before sharing
greybeard self-check --context "We're migrating auth to a new provider mid-sprint"

# Get help communicating a concern
greybeard coach --audience leadership --context "I think we're moving too fast"

# Review with repo context (README, git log, structure)
greybeard analyze --repo . --context "mid-sprint auth migration"

# List available packs
greybeard packs

# Start MCP server (for Claude Desktop, Cursor, Zed, etc.)
greybeard mcp

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Content Packs

Content packs define the perspective, tone, and heuristics used during review. They're plain YAML — human-editable, version-controllable, shareable.

Built-in Packs

Pack	Perspective	Focus
staff-core	Staff Engineer	Ops, ownership, long-term cost
oncall-future-you	On-call engineer, 3am	Failure modes, pager noise, recovery
mentor-mode	Experienced mentor	Teaching, reasoning, growth
solutions-architect	Solutions Architect	Entity modeling, boundaries, fit-for-purpose
idp-readiness	Platform Engineering	IDP maturity, automation vs process
platform-eng	Platform Engineer	DX, abstractions, tool maturity, team scaling
security-reviewer	AppSec Engineer	Auth, injection, secrets, overprivileged access
startup-pragmatist	Pragmatic Engineer	Complexity vs stage, reversibility, scope
incident-postmortem	SRE / On-call	Blameless analysis, root cause, action items
data-migrations	Migration Expert	Lock safety, zero-downtime, rollback, performance

Testing Packs

Each built-in pack includes an example markdown file you can test against:

# Test a pack with its example
cat packs/staff-core/STAFF-CORE-EXAMPLE.md | greybeard analyze --pack staff-core
cat packs/security-reviewer/SECURITY-REVIEWER-EXAMPLE.md | greybeard analyze --pack security-reviewer
cat packs/mentor-mode/MENTOR-MODE-EXAMPLE.md | greybeard analyze --pack mentor-mode --mode mentor

# See what's available
ls packs/*/README.md      # Get quick start for each pack
ls packs/*-EXAMPLE.md     # See all example files

Each pack folder contains:

• <pack-name>.yaml — The pack definition
• README.md — Quick start and focus areas
• <PACK>-EXAMPLE.md — A real-world scenario to test with

# Install all packs from a GitHub repo's packs/ directory
greybeard pack install github:someone/their-greybeard-packs

# Install a single pack file
greybeard pack install github:owner/repo/packs/my-pack.yaml

# Install from a raw URL
greybeard pack install https://example.com/my-pack.yaml

# See what's installed
greybeard pack list

# Remove a source
greybeard pack remove owner__repo

Installed packs are cached at ~/.greybeard/packs/ and available by name just like built-ins.

Custom Packs

Create a .yaml file and pass it directly:

cat design-doc.md | greybeard analyze --pack my-team.yaml

See examples/custom-pack.md for the pack schema.

Publishing a Pack

Create a public GitHub repo with a packs/ directory containing .yaml files. Anyone can install it with:

greybeard pack install github:your-handle/your-pack-repo

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MCP Integration

greybeard runs as a local MCP server, exposing its review tools to any compatible client.

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "greybeard": {
      "command": "greybeard",
      "args": ["mcp"]
    }
  }
}

Then restart Claude Desktop. You'll see greybeard tools available in the tool picker.

Cursor / Zed / Other MCP Clients

Any client that supports the MCP stdio transport works. Point it at greybeard mcp.

Available MCP Tools

Tool	Description
review_decision	Staff-level review of a decision or document
self_check	Review your own proposal before sharing
coach_communication	Get suggested language for a specific audience
list_packs	List available content packs

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Primary Review Lenses

The greybeard always reasons through four lenses:

1. Operational impact — failure modes, observability, deploy & rollback safety
2. Long-term ownership — who owns this in 6–12 months, tribal knowledge risk, accountability
3. On-call & human cost — pager noise, manual recovery, 3am failure scenarios
4. "Who pays for this later?" — complexity tax, maintenance burden, coordination overhead

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Output Format

All output is structured Markdown:

## Summary

...

## Key Risks

...

## Tradeoffs

...

## Questions to Answer Before Proceeding

...

## Suggested Communication Language

...

---

_Assumptions made: ..._

Save to a file with --output review.md.

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Design Decisions

• Multi-backend: OpenAI, Anthropic, Ollama, LM Studio. Configured via ~/.greybeard/config.yaml. All local backends require no API key.
• CLI-first: No web UI, no server. Designed to be piped into and out of.
• Stateless: No conversation history by default. Add --context for prior context.
• Pack format: YAML for human editability. Packs are loaded at runtime and validated loosely.
• Remote packs cached locally: ~/.greybeard/packs/<source>/ — installed once, used like built-ins.
• MCP stdio transport: The simplest, most compatible MCP integration. No HTTP server needed.
• Minimal deps: click, openai, pyyaml, rich, python-dotenv. Anthropic is optional.

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Contributing

We welcome contributions! 🎉

Quick Start:

• Content Packs: Create a folder in packs/<pack-name>/ with:

  • <pack-name>.yaml — The pack definition
  • README.md — Quick start and focus areas
  • <PACK>-EXAMPLE.md — A real-world scenario for testing

  Example: See packs/staff-core/ for the structure.

• Bug Reports: Open an issue

• Feature Requests: Suggest a feature

• Code: See the Contributing Guide for setup instructions

Community:

• Code of Conduct
• Security Policy
• Documentation

If you build a public pack repo on GitHub, feel free to open an issue linking to it — we'll add it to a community registry.