A seven-step software development toolkit based on append-only planning documents. It covers problem framing, requirements, design context, reviews, architecture decisions, and pull-request creation.

Use it to bootstrap the process, explore alternatives, write and review product requirements, record architecture decisions, migrate its configuration, and create pull requests.

It gives teams a documented path from an initial idea to a reviewed code change. Superseded documents remain traceable, helping people distinguish current requirements from old ones.

immutable — Plugin by choi88andys

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.

Claude Code

/plugin marketplace add choi88andys/skills

agentmods

npx agentmods add plugins/choi88andys/skills/immutable

Clone the repo

git clone --depth 1 https://github.com/choi88andys/skills

Made for: Claude Code.

Per session not measured What this adds to a session before it is invoked.

When invoked not measured Not applicable: nothing here is loaded into a session.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Security

Grade A, and why

immutable 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.

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.

immutable/.claude-plugin/plugin.json · 32 lines

What it actually says

{
  "name": "immutable",
  "version": "0.10.1",
  "description": "Append-only SDD toolkit covering the full 7-step flow from problem framing through PR creation. Skills: /immutable:init (starter bootstrap), /immutable:office-hours (premise + alternatives), /immutable:prd (pitch authoring — WHAT), /immutable:design (app-side context), /immutable:plan-review-ceo (scope challenge + adversarial review), /immutable:plan-review-eng (engineering review + worktree analysis), /immutable:adr (Architecture Decision Records — WHY), /immutable:ship (PR creation), /immutable:migrate (one-shot config + profile schema migration). Authoring skills enforce a grill-me interview, multi-persona adversarial review, and a 90% completeness gate. Ships a PostToolUse read gate (the plugin's first hook) that withholds the body of a deprecated doc at Read time, so a dead spec cannot be mistaken for current requirements. The flow runs standalone — no external harness required. Built from two layered fusions: the immutable-prd lineage (append-only artifacts with supersede chains for accuracy + accountability) and the gstack lineage (transient → artifact flow pipeline). See plugin README's Design heritage for the full origin story.",
  "author": {
    "name": "choi88andys"
  },
  "license": "MIT",
  "homepage": "https://github.com/choi88andys/skills",
  "repository": "https://github.com/choi88andys/skills",
  "keywords": [
    "sdd",
    "prd",
    "pitch",
    "adr",
    "architecture-decision",
    "append-only",
    "interview",
    "immutable",
    "init",
    "bootstrap",
    "starter",
    "migrate",
    "profile",
    "office-hours",
    "design",
    "plan-review",
    "ship",
    "spec-driven-development"
  ]
}

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.

2d ago First seen · 32 lines scan A bf822a82dc76

Subscribe to this mod's changes

immutable is a plugin published in the GitHub repository choi88andys/skills (9 stars, last pushed 1mo ago), licensed MIT. Its token cost is not measured: this kind of file is read by the harness, not the model. 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.

Code review Planning

immutable

Getting it into your agent

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

Other plugins, from other repositories

nextjs

nextjs

claude-plugins-official

knowledge-work-plugins

ecc

ecc