quick-plan

A planning tool that turns an existing conversation into a detailed implementation plan. TDD means test-driven development: defining tests as part of the work so the intended behavior can be checked.

In plain words
What is it for?
Use it to reconstruct goals and boundaries, explore the codebase with domain experts, divide the work into tasks, specify exact tests and commands, and save a plan for execution.
Why use it?
It helps when there is no written specification but the conversation contains requirements and decisions. It also reduces the need for the implementer to rediscover the intended work.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/existential-birds/beagle/quick-plan
Any agent
npx skills add existential-birds/beagle --skill quick-plan
Clone the repo
git clone --depth 1 https://github.com/existential-birds/beagle

Made for: Claude Code, Codex.

Per session 230 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,654 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00230 $0.04654
Opus 5 $0.00115 $0.02327
Sonnet 5 $0.00046 $0.00931
Haiku 4.5 $0.00023 $0.00465

Measured 3d ago against content hash 40fb78bb11fe, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

quick-plan scanned grade A with 0 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 3d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/beagle-analysis/skills/quick-plan/SKILL.md · 219 lines

How it starts

The opening of the file, as written. The whole thing — 219 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Quick Plan: Conversation Into Implementation Plan

Turn the work already discussed in this session into the same comprehensive, TDD-driven implementation plan write-plan produces — but without a spec. An engineer (or downstream agent) can execute it task-by-task without re-deriving intent.

The output is a single markdown plan at .beagle/plans/<slug>/plan.md. The plan captures HOW — file structure, task decomposition, exact tests, exact commands. Because there is no spec, quick-plan also captures the WHAT and WHY inside the plan, in an Intent header it synthesizes from the conversation and verifies before locking.

What Replaces the Spec

write-plan leans on a reviewed spec for three things. quick-plan reconstructs each, because skipping them is how plans bake in unexamined assumptions:

The spec gives write-plan… quick-plan reconstructs it from…
WHAT / WHY (requirements, core value, out-of-scope) The conversation — what the user has been asking for, correcting, and ruling out this session — distilled into an Intent Brief.
Key Decisions (vetted architectural choices) Fanout domain-expert subagents that recommend an approach grounded in this codebase's real patterns and the stack's idioms.
Reference Points (analogous existing code) The same fanout subagents, returning file:line analogs the plan mirrors.
A human-reviewed gate A gap check: proceed silently when the conversation is unambiguous; ask the user targeted questions only where intent has real holes.

The spec is a contract written before planning. quick-plan writes that contract during planning, from cheaper signals, and confirms only the load-bearing parts with the user. Everything downstream of the Intent Brief — task decomposition, TDD discipline, the recoverability test, the self-review gates — is identical to write-plan. Same output, different front-half.

Workflow

Complete these steps in order:

Read the full file on GitHub · 219 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 3d ago First seen · 219 lines · 230 tokens per session scan A 40fb78bb11fe

Subscribe to this mod's changes

quick-plan is a skill published in the GitHub repository existential-birds/beagle (79 stars, last pushed 23d ago), licensed Apache-2.0. It adds 230 tokens to every session and 4,654 once invoked, about $0.0011 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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