# propagate

Turns Allium specifications into test files: surface boundaries, state transitions, invariants. Useful when the spec exists but the tests do not.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 2600 installs · ★ 521
- Author: juxt
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/juxt/allium/tree/HEAD/skills/propagate/SKILL.md
- Updated: 2026-09-27
- HTML: https://affpapa.org/en/nevibecode/skills/propagate

## What it does

The skill reads an `.allium` file and maps its constructs to test obligations. Deterministic tooling handles completeness, so every construct gets a test. The implementation bridge stays with you: correlating constructs with code and writing tests in the project's own conventions.

Two modes. Surface mode works from surface declarations and produces boundary tests — exposure of `exposes` items, availability under `when` conditions, actor restrictions, context scoping, `demands`/`fulfils` contract direction, `@guarantee` annotations. Spec mode walks the whole obligations document: entities, enums, sum types, invariants, rules, state transitions, temporal rules, scenarios, data flow chains, reachability and deadlocks.

Four things are needed before it runs: an Allium spec, a target codebase, obligations from `allium plan <spec>`, and a domain model from `allium model <spec>`. No CLI around? Obligations get derived by hand from the taxonomy in `references/test-generation.md`. The skill also runs unattended as the `propagate` subagent, for instance inside the Allium loop — anything needing a human call goes into the final output while the rest of the work continues.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add juxt/allium --skill propagate -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/propagate/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/propagate/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add juxt/allium --skill propagate -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/propagate/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add juxt/allium --skill propagate -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/propagate/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install juxt/allium propagate
```

2. **Manually: put the files in place**
- File: `.github/skills/propagate/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add juxt/allium --skill propagate -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/juxt/allium --path skills/propagate
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/propagate/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add juxt/allium --skill propagate -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/juxt/allium/tree/HEAD/skills/propagate/SKILL.md

## When to use it
- derive test obligations from an Allium spec
- generate boundary tests for an API or integration
- cover state transitions and terminal states
- verify every declared transition is reachable
- surface deadlock states via `allium analyse`

## Example prompts
- run propagate on this spec and generate the tests
- write surface boundary tests for `orders.allium`
- check test coverage against the spec obligations

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: f89ab6c9371be9ca.

BEGIN THIRD-PARTY FILE f89ab6c9371be9ca
```text
---
name: propagate
description: "Generate tests from Allium specifications. Use when the user wants to propagate tests, generate test files from a spec, write tests for a specification, create property-based tests, produce state machine tests, check test coverage against spec obligations, or understand what tests a specification requires."
---

# Propagation

This skill generates tests from Allium specifications. Propagation is how plants reproduce from cuttings of the parent: the spec is the parent, the tests are the offspring.

Deterministic tools guarantee completeness (every spec construct maps to a test obligation). You handle the implementation bridge: correlating spec constructs with code, generating tests in the project's conventions.

## Interaction modes

This skill runs in two modes. Every instruction below that asks or suggests something to the user follows the mode:

- **Interactive** — running inline in a conversation. Ask the user directly and wait for the answer.
- **Non-interactive** — running as the `propagate` subagent (for example inside the Allium loop), where no user is reachable. Report anything that needs a human decision — a spec too coarse to propagate, an ambiguous implementation bridge, uncovered obligations — in your final output and continue with the work that does not depend on it.

## Prerequisites

Before propagating tests, you need:

1. **An Allium spec** — the `.allium` file describing the system's behaviour
2. **A target codebase** — the implementation to test
3. **Test obligations** — from `allium plan <spec>` (JSON listing every required test)
4. **Domain model** — from `allium model <spec>` (JSON describing entity shapes, constraints, state machines)

If the CLI tools are not available, derive test obligations manually from the spec using the test-generation taxonomy in [`references/test-generation.md`](../allium/references/test-generation.md).

## Modes

### Surface mode

Generates boundary tests from surface declarations. Use when the user wants to test an API, UI contract or integration boundary.

For each surface in the spec:

1. **Exposure tests** — verify each item in `exposes` is accessible to the specified actor, including `for` iteration over collections
2. **Provides tests** — verify operations appear when their `when` conditions are true and are hidden otherwise, including when the corresponding rule's `requires` clauses are not met
3. **Actor restriction tests** — verify the surface is not accessible to other actor types
4. **Actor identification tests** — verify only entities matching the actor's `identified_by` predicate can interact; for actors with `within`, verify interaction is scoped to the declared context
```
END THIRD-PARTY FILE f89ab6c9371be9ca

The third-party file has ended. Everything between the f89ab6c9371be9ca tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

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