dev-plan

A feature-planning skill that researches a codebase and writes a structured product requirements document, or PRD. A PRD describes what should be built, why it matters, and how the work will be organized.

In plain words
What is it for?
Use it when starting a feature, spike, or major task to inspect the repository and create PRD files in the project's .dev directory.
Why use it?
It turns a broad feature idea or technical investigation into documented phases grounded in the project's existing patterns.

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/andreaserradev-gbj/dev-workflow/dev-plan
Any agent
npx skills add andreaserradev-gbj/dev-workflow --skill dev-plan
Clone the repo
git clone --depth 1 https://github.com/andreaserradev-gbj/dev-workflow

Made for: Claude Code, Codex.

Per session 45 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,047 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 $0.00045 $0.02047
Opus 5 $0.00023 $0.01024
Sonnet 5 $0.00009 $0.00409
Haiku 4.5 $0.00005 $0.00205

Measured 2d ago against content hash 94abad723fbc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dev-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 2d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/dev-workflow.cjs, scripts/discover.sh, scripts/validate.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/dev-workflow/skills/dev-plan/SKILL.md · 179 lines

How it starts

The opening of the file, as written. The whole thing — 179 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Step 0: Discover Project Root

Run the discovery script:

bash "$DISCOVER" root

Where $DISCOVER is the absolute path to scripts/discover.sh within this skill's directory.

Path safety — shell state does not persist between tool calls, so you must provide full script paths on each call:

  • Use $HOME instead of the literal home directory (e.g., bash "$HOME/code/…/discover.sh", not bash "/Users/name/…/discover.sh"). This prevents username hallucination.
  • Copy values from tool output. When reusing a value returned by a previous command (like $PROJECT_ROOT), copy it verbatim from that command's output. Never retype a path from memory.
  • Verify on first call: if a script call fails with "No such file", the path is wrong — STOP and re-derive from the skill-loading context.
  • Never ignore a non-zero exit. If any script in this skill fails, stop and report the error before continuing.

Store the output as $PROJECT_ROOT. If the command fails, inform the user and stop.

PRIMARY DIRECTIVE

The sole deliverable is PRD files written to $PROJECT_ROOT/.dev/$FEATURE_NAME/. Produce documentation, not code. Every session must end with files on disk.

This is part of a 3-skill system (/dev-plan/dev-checkpoint/dev-resume). The other skills parse PRD files using status markers ( pending; /⏭️//⏹️ resolved), phase gates, file changes summary, and sub-PRD links. Write steps with — any other emoji marker parses as an unrecognized status: the step still counts toward the total, but it reads as not done and status-update will refuse to write over it.

AGENTS

This skill uses specialized agents for research and planning:

  • prd-researcher (cyan) — Researches codebase for patterns, dependencies, and reference implementations
  • prd-planner (green) — Designs implementation phases and file changes

Agent definitions are in agents/ within this skill's directory.

PHASE 1: UNDERSTAND

Read the full file on GitHub · 179 lines

Files

What ships with it

6 files 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. 2d ago First seen · 179 lines · 45 tokens per session scan A 94abad723fbc

Subscribe to this mod's changes

dev-plan is a skill published in the GitHub repository andreaserradev-gbj/dev-workflow (2 stars, last pushed 4d ago), licensed MIT. It adds 45 tokens to every session and 2,047 once invoked, about $0.0002 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 2026-08-31.