write-spec

SKILL.md

Write Spec

If you see unfamiliar placeholders or need to check which tools are connected, see CONNECTORS.md.

Write a feature specification or product requirements document (PRD).

Usage

/write-spec $ARGUMENTS

Workflow

1. Understand the Feature
Ask the user what they want to spec. Accept any of:

A feature name ("SSO support")

A problem statement ("Enterprise customers keep asking for centralized auth")

A user request ("Users want to export their data as CSV")

A vague idea ("We should do something about onboarding drop-off")

2. Gather Context

Ask the user for the following. Be conversational — do not dump all questions at once. Ask the most important ones first and fill in gaps as you go:

User problem: What problem does this solve? Who experiences it?

Target users: Which user segment(s) does this serve?

Success metrics: How will we know this worked?

Constraints: Technical constraints, timeline, regulatory requirements, dependencies

Prior art: Has this been attempted before? Are there existing solutions?

3. Pull Context from Connected Tools

If ~~project tracker is connected:

Search for related tickets, epics, or features

Pull in any existing requirements or acceptance criteria

Identify dependencies on other work items

If ~~knowledge base is connected:

Search for related research documents, prior specs, or design docs

Pull in relevant user research findings

Find related meeting notes or decision records

If ~~design is connected:

Pull related mockups, wireframes, or design explorations

Search for design system components relevant to the feature

If these tools are not connected, work entirely from what the user provides. Do not ask the user to connect tools — just proceed with available information.

4. Generate the PRD

Produce a structured PRD with these sections. See PRD Structure below for detailed guidance on what each section should contain.

Problem Statement: The user problem, who is affected, and impact of not solving it (2-3 sentences)

Goals: 3-5 specific, measurable outcomes tied to user or business metrics

Non-Goals: 3-5 things explicitly out of scope, with brief rationale for each

User Stories: Standard format ("As a [user type], I want [capability] so that [benefit]"), grouped by persona

Requirements: Categorized as Must-Have (P0), Nice-to-Have (P1), and Future Considerations (P2), each with acceptance criteria

Success Metrics: Leading indicators (change quickly) and lagging indicators (change over time), with specific targets

Open Questions: Unresolved questions tagged with who needs to answer (engineering, design, legal, data)

Timeline Considerations: Hard deadlines, dependencies, and phasing

5. Review and Iterate

After generating the PRD:

Ask the user if any sections need adjustment

Offer to expand on specific sections

Offer to create follow-up artifacts (design brief, engineering ticket breakdown, stakeholder pitch)

PRD Structure

Problem Statement

Describe the user problem in 2-3 sentences

Who experiences this problem and how often

What is the cost of not solving it (user pain, business impact, competitive risk)

Ground this in evidence: user research, support data, metrics, or customer feedback

Goals

3-5 specific, measurable outcomes this feature should achieve

Each goal should answer: "How will we know this succeeded?"

Distinguish between user goals (what users get) and business goals (what the company gets)

Goals should be outcomes, not outputs ("reduce time to first value by 50%" not "build onboarding wizard")

Non-Goals

3-5 things this feature explicitly will NOT do

Adjacent capabilities that are out of scope for this version

For each non-goal, briefly explain why it is out of scope (not enough impact, too complex, separate initiative, premature)

Non-goals prevent scope creep during implementation and set expectations with stakeholders

User Stories

Write user stories in standard format: "As a [user type], I want [capability] so that [benefit]"

Guidelines:

The user type should be specific enough to be meaningful ("enterprise admin" not just "user")

The capability should describe what they want to accomplish, not how

The benefit should explain the "why" — what value does this deliver

Include edge cases: error states, empty states, boundary conditions

Include different user types if the feature serves multiple personas

Order by priority — most important stories first

Example:

"As a team admin, I want to configure SSO for my organization so that my team members can log in with their corporate credentials"

"As a team member, I want to be automatically redirected to my company's SSO login so that I do not need to remember a separate password"

"As a team admin, I want to see which members have logged in via SSO so that I can verify the rollout is working"

Requirements

Must-Have (P0): The feature cannot ship without these. These represent the minimum viable version of the feature. Ask: "If we cut this, does the feature still solve the core problem?" If no, it is P0.

Nice-to-Have (P1): Significantly improves the experience but the core use case works without them. These often become fast follow-ups after launch.

Future Considerations (P2): Explicitly out of scope for v1 but we want to design in a way that supports them later. Documenting these prevents accidental architectural decisions that make them hard later.

For each requirement:

Write a clear, unambiguous description of the expected behavior

Include acceptance criteria (see below)

Note any technical considerations or constraints

Flag dependencies on other teams or systems

Open Questions

Questions that need answers before or during implementation

Tag each with who should answer (engineering, design, legal, data, stakeholder)

Distinguish between blocking questions (must answer before starting) and non-blocking (can resolve during implementation)

Timeline Considerations

Hard deadlines (contractual commitments, events, compliance dates)

Dependencies on other teams' work or releases

Suggested phasing if the feature is too large for one release

User Story Writing

Good user stories are:

Independent: Can be developed and delivered on their own

Negotiable: Details can be discussed, the story is not a contract

Valuable: Delivers value to the user (not just the team)

Estimable: The team can roughly estimate the effort

Small: Can be completed in one sprint/iteration

Testable: There is a clear way to verify it works

Common Mistakes in User Stories

Too vague: "As a user, I want the product to be faster" — what specifically should be faster?

Solution-prescriptive: "As a user, I want a dropdown menu" — describe the need, not the UI widget

No benefit: "As a user, I want to click a button" — why? What does it accomplish?

Too large: "As a user, I want to manage my team" — break this into specific capabilities

Internal focus: "As the engineering team, we want to refactor the database" — this is a task, not a user story

Requirements Categorization

MoSCoW Framework

Must have: Without these, the feature is not viable. Non-negotiable.

Should have: Important but not critical for launch. High-priority fast follows.

Could have: Desirable if time permits. Will not delay delivery if cut.

Won't have (this time): Explicitly out of scope. May revisit in future versions.

Tips for Categorization

Be ruthless about P0s. The tighter the must-have list, the faster you ship and learn.

If everything is P0, nothing is P0. Challenge every must-have: "Would we really not ship without this?"

P1s should be things you are confident you will build soon, not a wish list.

P2s are architectural insurance — they guide design decisions even though you are not building them now.

Success Metrics Definition

Leading Indicators

Metrics that change quickly after launch (days to weeks):

Adoption rate: % of eligible users who try the feature

Activation rate: % of users who complete the core action

Task completion rate: % of users who successfully accomplish their goal

Time to complete: How long the core workflow takes

Error rate: How often users encounter errors or dead ends

Feature usage frequency: How often users return to use the feature

Lagging Indicators

Metrics that take time to develop (weeks to months):

Retention impact: Does this feature improve user retention?

Revenue impact: Does this drive upgrades, expansion, or new revenue?

NPS / satisfaction change: Does this improve how users feel about the product?

Support ticket reduction: Does this reduce support load?

Competitive win rate: Does this help win more deals?

Setting Targets

Targets should be specific: "50% adoption within 30 days" not "high adoption"

Base targets on comparable features, industry benchmarks, or explicit hypotheses

Set a "success" threshold and a "stretch" target

Define the measurement method: what tool, what query, what time window

Specify when you will evaluate: 1 week, 1 month, 1 quarter post-launch

Acceptance Criteria

Write acceptance criteria in Given/When/Then format or as a checklist:

Given/When/Then:

Given [precondition or context]

When [action the user takes]

Then [expected outcome]

Example:

Given the admin has configured SSO for their organization

When a team member visits the login page

Then they are automatically redirected to the organization's SSO provider

Checklist format:

 Admin can enter SSO provider URL in organization settings

 Team members see "Log in with SSO" button on login page

 SSO login creates a new account if one does not exist

 SSO login links to existing account if email matches

 Failed SSO attempts show a clear error message

Tips for Acceptance Criteria

Cover the happy path, error cases, and edge cases

Be specific about the expected behavior, not the implementation

Include what should NOT happen (negative test cases)

Each criterion should be independently testable

Avoid ambiguous words: "fast", "user-friendly", "intuitive" — define what these mean concretely

Scope Management

Recognizing Scope Creep

Scope creep happens when:

Requirements keep getting added after the spec is approved

"Small" additions accumulate into a significantly larger project

The team is building features no user asked for ("while we're at it...")

The launch date keeps moving without explicit re-scoping

Stakeholders add requirements without removing anything

Preventing Scope Creep

Write explicit non-goals in every spec

Require that any scope addition comes with a scope removal or timeline extension

Separate "v1" from "v2" clearly in the spec

Review the spec against the original problem statement — does everything serve it?

Time-box investigations: "If we cannot figure out X in 2 days, we cut it"

Create a "parking lot" for good ideas that are not in scope

Output Format

Use markdown with clear headers. Keep the document scannable — busy stakeholders should be able to read just the headers and bold text to get the gist.

Tips

Be opinionated about scope. It is better to have a tight, well-defined spec than an expansive vague one.

If the user's idea is too big for one spec, suggest breaking it into phases and spec the first phase.

Success metrics should be specific and measurable, not vague ("improve user experience").

Non-goals are as important as goals. They prevent scope creep during implementation.

Open questions should be genuinely open — do not include questions you can answer from context.