tiny-spec

A tiny, opinionated take on spec-driven development.

tiny-spec is a four-step workflow for Claude Code that turns a ticket into shipped, reviewed code. You write the intent, it produces a design, a task list, and then builds the work one task at a time. Every task is implemented by one agent and graded by an independent reviewer that runs the real tests before anything is committed.

That core is four skills and two agents. In front of it sit two optional planning on-ramps — tiny-spec-prd (idea → PRD) and tiny-spec-breakdown (PRD → stories) — for when you're starting from an idea rather than a ready ticket. tiny-spec-run walks the three planning steps in one command. No config file, no build step.

                                           ┌───────────────── tiny-spec-run ─────────────────┐
                                           │     optional: one command, stops before build   │
                                           ▼                                                 ▼
PLANNING (optional on-ramps)              EXECUTION (the core loop, one story at a time)
  tiny-spec-prd  ⇢  tiny-spec-breakdown ⇢  tiny-spec-create → tiny-spec-plan → tiny-spec-tasks → tiny-spec-build
  idea → PRD        PRD → stories           intent             design           tasks            per-task loop
  PRD.md            BREAKDOWN.md            SPEC.md            PLAN.md +        tasks.md         plan → implement → review → commit
                                                              constitution

The two on-ramps are optional and stack. Have nothing written down? Run tiny-spec-prd to interview your idea into a PRD.md. Have a PRD already? Run tiny-spec-breakdown to carve it into a BREAKDOWN.md — a flat list of Features → Stories with draft acceptance criteria. Have a single known piece of work? Skip both and start at tiny-spec-create. Both on-ramps write a regenerable file at your project root (not under .spec/); tiny-spec-create then reads the breakdown one story at a time.

New to spec-driven development?

Spec-driven development (SDD) means writing down what you want and why before any code exists, then letting that spec drive the build. Instead of prompting an agent and hoping, you hand it a small, explicit contract — the intent, a design, and an ordered list of tasks — and it implements against that. The payoff: the agent stops guessing. It knows what "done" looks like, you can review the plan before a single line is written, and the result is checked against the spec rather than vibes. tiny-spec is one small take on that idea.

Quickstart

Install the skills and agents into your Claude Code config with uv:

uvx tiny-spec install

Restart Claude Code so it picks up the new skills, then run the flow in your project:

/tiny-spec-prd       # optional: interview a rough idea into a PRD (PRD.md)
/tiny-spec-breakdown # optional: carve a PRD + wireframes into stories (BREAKDOWN.md)
/tiny-spec-create    # capture intent and requirements (binds a ticket, optional)
/tiny-spec-plan      # turn the spec into a design and harden the constitution
/tiny-spec-tasks     # slice the plan into an ordered checklist
/tiny-spec-build     # build each task: implement, review, commit

Or collapse the three planning steps into one and go straight to building:

/tiny-spec-run       # create → plan → tasks in one pass; stops before build
/tiny-spec-build     # build each task: implement, review, commit

tiny-spec-run resolves where your ticket stands and invokes whichever of create / plan / tasks moves it forward, reconciling anything stale first. It stops before tiny-spec-build — that's where you actually review the work — and it writes nothing itself, it only delegates.

Re-run install any time to update; tiny-spec uninstall removes only what it installed. Each skill is copied (not symlinked) so every install is self-contained.

git clone https://github.com/GrayMa77er/tiny-spec.git
cd tiny-spec

mkdir -p "$HOME/.claude/skills" "$HOME/.claude/agents"
for s in tiny-spec-prd tiny-spec-breakdown tiny-spec-run tiny-spec-create tiny-spec-plan tiny-spec-tasks tiny-spec-build; do
  cp -R "$s" "$HOME/.claude/skills/$s"
done
cp agents/*.md "$HOME/.claude/agents/"

How it works

The constitution (constitution.md) is the spine. tiny-spec-create seeds it from a short interview, tiny-spec-plan hardens it with concrete engineering rules, and tiny-spec-build injects it whole into every task. It holds your style, standards, invariants, definition of done, and verification commands.

Because it is project-wide it can also go missing — deleted, or never committed — while your specs survive. Re-running tiny-spec-create then repairs it: it rebuilds the constitution from whatever is already written down and marks completed tasks stale, since they were reviewed against a document that wasn't there.

Designs, if you have them

Drop your exported wireframes in a design/ directory and tiny-spec-create will look at them — actually look, they are read as images. From all of them together it proposes one coherent design system (spacing scale, type scale, color roles) for your approval and writes it into the constitution, then describes each screen as a D<n> entry in SPEC.md: its layout, its elements with a selector each, and the states it must render — all in those token names.

The point is what happens at build time. Tag a task with design: D1 and the reviewer renders that surface, measures the selectors the entry names, and fails the task on a value that isn't on your scale, an element that never got built, or a state the design calls for and the code doesn't render. It measures numbers rather than diffing screenshots, because pixel diffs go flaky and get muted. Tasks without a design: tag are graded exactly as before.

No Figma token, no plugin, no design SaaS — a view-only Figma works fine, since the committed export is what the agents read and the source: link keeps the trail back. Change an export and its recorded hash stops matching, which marks the spec stale the same way editing a requirement does. Skip the whole thing for a CLI or a library; the constitution simply has no design section.

tiny-spec-build walks the task list top to bottom. Each task runs through one loop:

1. Plan the task against the constitution (inline, brief).
2. Implement it with a fresh tiny-spec-build-executor agent.
3. Review it with an independent tiny-spec-build-reviewer agent that runs the gate end to end and grades against the constitution and the task's acceptance.
4. On pass, commit the code plus a checklist tick. On fail, loop back to the executor with the findings. After two failed attempts it becomes a blocker.

flowchart TB
    SPEC[SPEC.md<br/>intent] --> PLAN[PLAN.md<br/>design] --> TASKS[tasks.md<br/>checklist]

    TASKS --> P[Plan task]
    P --> I[Implement<br/>executor]
    I --> R[Review + run gate<br/>reviewer]
    R -->|pass| C[Commit + tick]
    C --> TASKS
    R -->|fail| I
    R -->|fail twice| B[Blocker logged to decisions.md]

    CON([constitution.md]) -.-> P & I & R
    MEM([memory.md]) -.-> I & R
    DES([SPEC.md D-n + design/ export]) -.->|only on a design: task| I & R

Solid arrows are the flow. Dotted arrows show the persistent context injected into a step: the constitution.md goes into planning, implementation, and review, while memory.md is handed to the executor and reviewer. A task tagged design: also carries its screen's D<n> entry into both agents — and the review step then runs the visual: gate on top of the usual one.

A small memory.md carries operational lessons between runs, so the executor and reviewer (which start fresh each time) don't relearn the same pitfalls.

When a task can't pass because of a gap in the design or spec, the executor stops and logs a blocker instead of hacking around it. You fix the gap upstream in tiny-spec-plan or tiny-spec-create, then resume. Work runs one ticket at a time and resumes from the checklist state.

Why it's small

Most spec frameworks are generous by default: many phases, many agents, many generated documents. tiny-spec makes the opposite bet. Keep one safeguard, drop the rest.

A green unit test suite is not the same as working software, so the reviewer exercises acceptance criteria end to end and a final smoke test confirms the whole spec. That independent review is the safeguard — not the volume of planning artifacts. One task, one commit, an external reviewer. Nothing gets added unless it earns its place.

The case for staying small:

• Documents are context, and context isn't free. Generating large spec.md, plan.md, research.md, and data-model.md files costs tokens to write, then costs context to carry. Every paragraph the agent has to hold is room it no longer has for your actual code. tiny-spec keeps the spine small — a constitution and a short memory — and injects only what each task needs.
• Real work is a ticket inside a system, not a greenfield repo. Bigger kits assume you're bootstrapping a project from a blank page. Day to day, you pick up a ticket and change part of a system that already exists. tiny-spec binds to a ticket, works one at a time, and references your task platform instead of re-describing the world.
• Rigid pipelines fight the user. Mandatory phases and required sections impose ceremony on work that doesn't need it. tiny-spec's extra structure is optional by design — add shape where it pays, skip it where it doesn't.
• More moving parts is more to maintain. Orchestrators, ownership contracts, checkpoint matrices, and config files are themselves a system you have to learn and keep in sync. A few small skills and two agents are not.
• Generated docs can fake rigor. A folder of polished planning artifacts looks like progress, but it isn't proof. The proof is the reviewer running your real tests before each commit.

That's the whole trade: where larger kits add machinery, tiny-spec adds one independent reviewer and stops.

Project layout

Each skill is one self-contained SKILL.md, with every document skeleton inline in it — no companion template files, no absolute paths, and no shared parent required at runtime, so a skill works wherever you drop it. (It also means a run never stops to ask permission to read a template out of your Claude config directory.)

tiny-spec creates a .spec/ directory in your project root, never inside a skill. It is namespaced per ticket, with a shared spine at the root:

.spec/
  constitution.md           project-wide, shared across tickets
  memory.md                 operational lessons, shared across tickets
  <ticket-id>/              one directory per ticket (PROJ-123/, gh-42/, …)
    SPEC.md  PLAN.md  tasks.md  decisions.md

PRD.md, BREAKDOWN.md, and design/ sit at your project root rather than inside .spec/, because they are yours: the first two are regenerable pre-spec planning files, and the design exports are project files no skill ever writes.

CONTRACTS.md documents the formats for maintainers. The skills do not read it at runtime; each is self-sufficient.

Integrations

tiny-spec binds to a task platform (Jira, GitHub Issues, Azure DevOps, Monday) by reference only: a ticket block in the spec and a Refs: footer on each Conventional Commit, so the platform auto-links the work. No API calls or credentials are required.

Contributing

Issues and pull requests are welcome. See CONTRIBUTING.md, and read AGENTS.md before changing any skill or agent.

License

MIT