spec-generator

●─▶●─▶●─▶● spec-generator

What it does

Takes a plain-language feature description and produces a structured Markdown specification. Four steps build on each other: analyze extracts actors and behaviors, expand-requirements generates FRs, NFRs, edge cases, validation rules, error handling, and authorization requirements, derive-criteria writes Given/When/Then acceptance criteria for each FR, and write-spec assembles the final document.

Sample output

The flow writes feature-spec.md to the run directory. The document follows this structure:

# <feature-name> Feature Specification

## Summary
...

## Functional Requirements
1. <FR-001> ...

## Non-Functional Requirements
- <NFR-001> ...

## Edge Cases
- <EC-001> ...

## Validation Rules
- <VR-001> ...

## Error Handling
- <EH-001> <scenario>: <response>

## Authorization
- <AUTH-001> ...

## Acceptance Criteria
- [ ] <AC-001> Given ..., when ..., then ...

Estimated cost and duration

• Cost: $0.05–$0.30 per run (billed to your subscription on Pro/Max).
• Duration: 2–10 minutes depending on feature complexity and model choice.

Install

relay install spec-generator

Run

relay run spec-generator --featureDescription="Users can reset their password via a link sent to their registered email address"

Configuration

| Field | Type | Default | Notes | |---|---|---|---| | featureDescription | string | (required) | Plain-language description of the feature to specify. |

Models per step (override via relay run spec-generator --model.<step>=<model>):

| Step | Default model | |---|---| | analyze | sonnet | | expand-requirements | sonnet | | derive-criteria | sonnet | | write-spec | sonnet |

Customization

Fork the flow:

relay install spec-generator
mv ./.relay/flows/spec-generator ./my-spec-generator
cd ./my-spec-generator

Common customizations:

• Add a section — extend schemas/requirements.ts and update prompts/02_expand-requirements.md and prompts/04_write-spec.md.
• Upgrade a step for higher quality — set model: 'opus' on expand-requirements or derive-criteria in flow.ts.
• Enforce minimum counts — add .min(3) to arrays in schemas/requirements.ts so the validator rejects thin specs.
• Rename the output file — change the artifact value on write-spec in flow.ts to match your naming convention.

License

MIT. Copyright Ganderbite.