beagle

github.com/existential-birds/beagle

Overview

Beagle is a Claude Code plugin marketplace, the shared repository of agent skills that every other Existential Birds tool draws on. It ships 131 skills covering code review, documentation, testing, strategy, and planning across Python, Go, Rust, Elixir, React, and iOS.

Write a skill once and it works everywhere the marketplace is installed: Daydream uses Beagle review skills as its per-stack review backends, and Amelia's Claude Code skills and commands ship through the same marketplace.

Design decisions

  • Verification before verdicts. Every review skill runs a mandatory verification protocol before reporting findings. Gate 0 is anti-confabulation: the reviewer must echo the exact file, line, and code it read before issuing any verdict. Further gates check evidence, severity, and format, with per-issue-type rules: flagging an "unused variable" requires a repo-wide reference search first. The goal is fewer false positives.
  • Reviews that learn. Every finding is logged with a human verdict (accept, reject, defer, acknowledge) and the skill rule that fired. A skill-improver aggregates per-rule rejection rates from those logs and emits evidence-bound edits back to the skills themselves.
  • Portability as a gate. All skills conform to the Agent Skills spec; a repo check fails on any harness-specific pattern in any skill file.
  • Coherent per-stack suites. Review, docs, and testing skills within a stack share output formats and load the same verification protocol. Reference files are distilled from primary sources: the Rust review checks were built chapter by chapter from Rust for Rustaceans.

Beyond code review

The marketplace also covers writing and thinking work:

  • Documentation. beagle-docs organizes writing around Diátaxis doc types: draft-docs generates first drafts from code analysis, improve-doc classifies a doc's sections by type and refines each one interactively, and ensure-docs finds coverage gaps. review-ai-writing detects robotic AI prose in docs, commit messages, and comments; humanize-beagle rewrites it.
  • Strategy. strategy-interview builds a strategy through guided conversation; strategy-review stress-tests an existing strategy document across seven dimensions, from diagnosis quality to falsifiability.
  • Idea to plan. prfaq-beagle pressure-tests a concept with Amazon's Working Backwards format and returns a pass/fail verdict. On pass, brainstorm-beagle shapes the idea into a WHAT/WHY spec through structured dialogue, and write-plan turns the spec into a TDD implementation plan of bite-sized steps.

Install

Add the marketplace, then install the plugins you need:

claude plugin marketplace add https://github.com/existential-birds/beagle

claude plugin install beagle-elixir@existential-birds

Verify the install by opening a new Claude Code session and running one of the plugin's skills, for example /beagle-elixir:review-elixir. If the skill loads, the plugin is active.

To use the skills with other AI agents such as Codex, install through the skills CLI:

npx skills add existential-birds/beagle

Per-plugin skill catalogs and setup details live in the repo README.

Plugin catalog

Skills are grouped into ten domain-namespaced plugins:

Plugin Skills Category
beagle-core 19 Shared workflows, verification, git, skill tooling
beagle-python 7 Python, FastAPI, SQLAlchemy, pytest
beagle-go 13 Go, BubbleTea, Wish SSH, Prometheus
beagle-elixir 11 Elixir, Phoenix, LiveView, ExUnit, ExDoc
beagle-ios 16 Swift, SwiftUI, SwiftData, iOS frameworks
beagle-react 28 React, React Flow, shadcn/ui, Tailwind, Remix v2
beagle-rust 12 Rust, tokio, axum, sqlx, serde
beagle-docs 10 Documentation quality, Diátaxis doc types, AI writing detection
beagle-analysis 13 Brainstorming, ADRs, strategy, LLM-as-judge, spec gaps, TDD plans
beagle-testing 2 Test plan generation and execution
Total 131 —

Each plugin exposes canonical entry-point skills, such as review-elixir, review-frontend, and review-go for stack-specific code review.

Source

github.com/existential-birds/beagle