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AI‑Assisted Feature Briefs: 7 Prompts & a 1‑Page Schema That Produce Contractor‑Ready Specs

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AI‑ASSISTED FEATURE BRIEFS: 7 PROMPTS & A 1‑PAGE SCHEMA THAT PRODUCE CONTRACTOR‑READY SPECS

App IdeasSeptember 29, 20266 min read1,195 words

Founders waste weeks iterating vague PRDs and answering contractor questions. This guide shows an operational approach: seven LLM prompt templates that produce contractor‑ready deliverables, a one‑page output schema that maps to OpenAPI, Figma slices and acceptance tests, plus concrete checks to prevent hallucination and scope creep. Copy the prompts, adapt the schema, and use the acceptance checklist for smoother handoffs.

ai-assisted-feature-briefsfeature brief templateLLM product spec promptsOpenAPI briefcontractor-ready specsAppWispr

Section 1

The 1‑Page Output Schema: what the contractor actually needs

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Deliver a single page that a contractor can open and start implementing. The one‑page schema bundles three machine‑readable outputs: (A) a minimal OpenAPI snippet (server URL, paths, request/response examples), (B) Figma slice requirements (frames, assets, exported layer names, export sizes), and (C) acceptance tests (Playwright / Cypress scenario names, steps, expected assertions). That combination makes both the design and dev work deterministic and reduces back‑and‑forth.

Structure the page as compact key/value sections: identity (name, owner, deadline), success criteria (measurable acceptance), API contract (OpenAPI YAML), UI slices (frame names, pixel sizes, interactions), and tests (test name, preconditions, steps, expected result). Include example values so contractors can validate the brief quickly and run the mock server immediately.

  • Identity & context: feature name, product area, owner, priority
  • Success criteria: 1–3 measurable acceptance statements
  • OpenAPI: baseUrl, endpoint path, method, request schema, response schema, 2 realistic examples
  • Figma slices: frame id/name, export formats, interaction notes
  • Acceptance tests: test id, precondition, steps, expected assertions

Section 2

Seven tested prompts (copy‑paste) that produce contractor‑ready sections

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Below are seven purpose‑built prompts. Use them in sequence: (1) Context extractor, (2) Success criteria generator, (3) API contract generator, (4) UI slice specifier, (5) Acceptance test generator, (6) Risk & edge case enumerator, (7) Handoff checklist generator. Each prompt focuses an LLM on one concrete output to reduce scope creep and reduce folding too many responsibilities into a single pass.

When you run them, always prefix with a short context block (product, personas, constraints, out‑of‑scope). Keep each prompt strict about format—ask for YAML or JSON—so outputs are machine‑parsable and easy to validate.

  • Prompt 1 — Context extractor: "Given this 3‑line product context, return a compact JSON with personas, constraints, and out‑of‑scope items."
  • Prompt 2 — Success criteria: "Produce 1–3 measurable acceptance statements (numeric where possible)."
  • Prompt 3 — API generator: "Emit an OpenAPI 3 fragment with paths, request/response, and two realistic examples."
  • Prompt 4 — Figma slices: "List frames to export, export names, dimensions, and interactions in JSON."
  • Prompt 5 — Acceptance tests: "Write Playwright test scenarios with setup, steps, and assertable outcomes."
  • Prompt 6 — Risks & edge cases: "Enumerate 6 likely failure modes and the expected behavior for each."

Section 3

Concrete output examples: OpenAPI + Figma slice + a Playwright test

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Example snippets let contractors validate faster. For OpenAPI, include method, path, body schema and two example request/response pairs. For Figma, include explicit frame names and exact export names so design exports match the code. For tests, provide Playwright-style steps that map directly to UI interactions and API stubs.

Machine‑readable examples mean you can wire automated validations into CI: validate OpenAPI with an OpenAPI linter, run Figma export regressions, and execute acceptance tests against a mock server. This turns the brief into an executable contract rather than prose.

  • OpenAPI: POST /checkout/session — body fields, 200 response with sample JSON
  • Figma: frame 'Checkout/Payment' — export as 'checkout_payment@2x.png' and include interactions 'click pay -> open modal'
  • Playwright test: setup (seed test user), steps (fill card, click pay), assert (200 from mock endpoint + thank you modal visible)

Section 4

Checks to prevent hallucinations and scope creep

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LLMs hallucinate when asked open, unconstrained questions. Use layered grounding and verification: (A) feed only canonical, short context (product doc, API catalog), (B) ask for outputs in strict JSON/YAML, (C) run an automated validator (schema linter, unit tests), and (D) human‑in‑the‑loop review for any invented IDs or undocumented endpoints. These steps shift the LLM from 'author' to 'formatter + enumerator'.

To stop scope creep, require that every feature brief include an explicit 'out of scope' list and a single 'success metric' that the contractor signs off on before work begins. If the LLM suggests additional features, capture them as backlog items rather than acceptance criteria.

  • Grounding: attach or reference canonical docs; prefer retrieval‑augmented generation (RAG) when domain facts matter.
  • Formatting constraints: require JSON/YAML with a schema and validate automatically.
  • Human check: verify any external IDs (product IDs, price IDs) and system behaviors before developer work begins.
  • Scope discipline: acceptance = pass/fail metric; extra ideas → backlog ticket.

Section 5

Practical workflow: from idea to contractor in two hours

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Workshop the idea for 15–30 minutes and collect context (owner, deadline, constraints). Run the seven prompts in sequence, validate the OpenAPI snippet with a linter, export Figma slices (or request exact export names), and run the generated acceptance tests against a mocked server. Reserve one hour for a quick human review and a 30‑minute contractor kickoff—ideally the contractor should be able to run the mock server and pass at least one acceptance test during the kickoff.

Instrument the process: keep a brief version history, add a 'validated by' line for the human reviewer, and store the machine outputs in a repo. Over time, track which prompts required manual edits; shrink those by adjusting prompt wording and adding context documents to your RAG store.

  • 0–30min: capture context and constraints
  • 30–60min: run prompts 1–4 (context, success criteria, API, UI)
  • 60–90min: run prompts 5–7 (tests, risks, handoff checklist) and validate outputs
  • 90–120min: human review + contractor kickoff with mock server and test run

FAQ

Common follow-up questions

Can I trust an LLM to produce an accurate OpenAPI spec?

LLMs can generate usable OpenAPI fragments but should not be trusted without validation. Always require the LLM to emit strict OpenAPI YAML/JSON, then run an OpenAPI linter and a small set of automated unit tests against a mock server. Treat the LLM output as a draft that must pass machine validation and a human quick‑audit before being handed to contractors.

How do I stop the LLM from inventing API endpoints or product IDs?

Ground generation with authoritative references (your existing API catalog or a short canonical context). Use RAG or attach the exact canonical doc to the prompt. Also require the LLM to flag any IDs as placeholders and include an explicit 'verify' checklist item for the contractor to confirm real ID values in staging.

What if the contractor asks for more detail after the brief?

Design the brief to minimize ambiguity: include example payloads, frame names, and test steps. If follow‑ups occur, capture them as scope‑control items. Use the 'out of scope' section to prevent informal scope growth and convert feature requests into backlog tickets with their own acceptance criteria.

Which tools should I use to validate the outputs automatically?

Run an OpenAPI linter (openapi‑validator), a schema validator for the UI export names, and run acceptance tests in CI (Playwright or Cypress). For hallucination checks, use document retrieval methods (RAG) and an LLM 'judge' prompt that compares output to the canonical context and returns a pass/fail with highlighted mismatches.

Sources

Research used in this article

Each generated article keeps its own linked source list so the underlying reporting is visible and easy to verify.

Next step

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