speckit-scope-estimate

name	speckit-scope-estimate
description	Estimate effort from spec complexity, requirement count, task phases, and technical decisions
compatibility	Requires spec-kit project structure with .specify/ directory
metadata	{"author":"github-spec-kit","source":"scope:commands/speckit.scope.estimate.md"}

Effort Estimation

Analyze spec artifacts and produce a structured effort estimate — breaking down work by phase, requirement, and complexity. Gives product managers and tech leads a data-driven answer to "how long will this take?" based on what's actually in the spec, not gut feelings.

User Input

$ARGUMENTS

You MUST consider the user input before proceeding (if not empty). The user may specify:

• Team size (e.g., "solo developer", "team of 3")
• Experience level (e.g., "senior", "junior", "mixed")
• Time unit preference (e.g., "hours", "days", "story points")
• Confidence level (e.g., "optimistic", "realistic", "pessimistic")
• Specific phase or requirement to estimate

Prerequisites

1. Confirm you are inside a git repository.
2. Verify .specify/ directory exists with at least spec.md.
3. Read spec.md to extract all requirements, scenarios, and success criteria.
4. If plan.md exists, read it for technical complexity signals (new tech, integrations, migrations).
5. If tasks.md exists, read it for phase structure and task granularity.

Outline

1. Calculate Complexity Score: Analyze spec artifacts to produce a complexity rating.

   • Requirement count: Number of distinct requirements in spec.md
   • Scenario count: Number of user scenarios
   • Integration count: External services, APIs, databases mentioned
   • Decision count: Technical decisions in plan.md
   • Task count: Total tasks in tasks.md
   • Phase count: Number of implementation phases

   ## Complexity Analysis
   
   | Factor | Count | Weight | Score |
   |--------|-------|--------|-------|
   | Requirements | 8 | x2 | 16 |
   | User Scenarios | 3 | x3 | 9 |
   | External Integrations | 2 | x5 | 10 |
   | Technical Decisions | 4 | x2 | 8 |
   | Task Items | 14 | x1 | 14 |
   | Implementation Phases | 3 | x3 | 9 |
   | **Total Complexity** | | | **66** |
   
   | Range | Level |
   |-------|-------|
   | 0-30 | 🟢 Simple |
   | 31-60 | 🟡 Moderate |
   | 61-100 | 🟠 Complex |
   | 100+ | 🔴 Very Complex |
   
   **This spec: 🟠 Complex (66)**
   

2. Estimate by Phase: Break down effort per implementation phase.

   ## Phase Estimates
   
   | Phase | Tasks | Estimate | Includes |
   |-------|-------|----------|----------|
   | Phase 1: Setup | 4 | 4-6 hours | Project scaffold, dependencies, config |
   | Phase 2: Core Auth | 6 | 12-18 hours | Signup, login, JWT, middleware |
   | Phase 3: Admin | 4 | 8-12 hours | Dashboard, user management |
   | Testing & QA | — | 6-10 hours | Unit, integration, E2E tests |
   | Code Review & Polish | — | 3-5 hours | PR prep, documentation |
   | **Total** | **14** | **33-51 hours** | |
   

3. Estimate by Requirement: Show effort per individual requirement.

   ## Requirement Estimates
   
   | Requirement | Complexity | Estimate | Risk |
   |-------------|-----------|----------|------|
   | REQ-001: User signup | Medium | 4-6h | Low |
   | REQ-002: User login | Medium | 3-5h | Low |
   | REQ-003: JWT tokens | High | 5-8h | Medium (security-critical) |
   | REQ-004: Rate limiting | High | 4-6h | Medium (perf testing needed) |
   | REQ-005: Email verification | High | 6-8h | High (external SMTP dependency) |
   

4. Risk Buffer Calculation: Add buffer based on uncertainty.

   ## Risk Buffer
   
   | Risk Factor | Buffer |
   |-------------|--------|
   | External integrations (2) | +15% |
   | Security-critical features | +10% |
   | First time with this tech stack | +20% |
   | **Total Buffer** | **+25%** (compound, capped) |
   
   | Estimate | Hours |
   |----------|-------|
   | Base estimate | 33-51h |
   | With risk buffer (+25%) | 41-64h |
   | **Recommended** | **~50 hours** (midpoint with buffer) |
   

5. Three-Point Estimate: Provide optimistic, realistic, and pessimistic.

   ## Three-Point Estimate
   
   | Scenario | Hours | Days (8h/day) | Weeks |
   |----------|-------|---------------|-------|
   | 🟢 Optimistic | 33h | 4.1 days | ~1 week |
   | 🟡 Realistic | 50h | 6.3 days | ~1.5 weeks |
   | 🔴 Pessimistic | 72h | 9.0 days | ~2 weeks |
   

6. Output: Deliver the complete estimate report.

Rules

• Read-only — never modify any files, only analyze and report
• Data-driven — every estimate must trace to specific spec content (requirement count, task count, integration count), never arbitrary
• Range-based — always give ranges, never single-point estimates
• Three-point — always include optimistic, realistic, and pessimistic scenarios
• Buffer-explicit — clearly show what risk buffer is added and why
• No false precision — don't estimate to the minute; use hour ranges for small specs, day ranges for large ones
• Transparent methodology — show the complexity scoring formula so estimates can be challenged and refined
• Team-aware — adjust estimates if user specifies team size or experience level