Calculate story point estimates for user stories using structured formula (Complexity × Effort + Risk). Analyzes acceptance criteria, assesses complexity (1-5), effort (1-5), and risk (0-3), then documents estimation rationale. Use during backlog grooming or sprint planning when stories need sizing.
Calculate story point estimates for user stories using structured formula (Complexity × Effort + Risk). Analyzes acceptance criteria, assesses complexity (1-5), effort (1-5), and risk (0-3), then documents estimation rationale. Use during backlog grooming or sprint planning when stories need sizing.
acceptance
[{"story_loaded":"Story file successfully loaded with acceptance criteria"},{"complexity_assessed":"Complexity score (1-5) calculated with detailed rationale based on technical difficulty"},{"effort_assessed":"Effort score (1-5) calculated with rationale based on work volume"},{"risk_assessed":"Risk adjustment (0-3) calculated with rationale based on unknowns"},{"story_points_calculated":"Story points calculated using formula: (Complexity × Effort) + Risk"},{"estimation_documented":"Estimation block added to story file with formula, breakdown, and assumptions"}]
inputs
{"story_id":{"type":"string","required":true,"description":"Story identifier (e.g., 'story-auth-001')","validation":"Must match pattern: story-{component}-{number}-{slug}"},"story_file":{"type":"string","required":true,"description":"Path to story markdown file"},"batch_mode":{"type":"boolean","required":false,"description":"Whether estimating multiple stories (for consistency checks)","default":false},"config_file":{"type":"string","required":false,"description":"Path to config with velocity baseline (defaults to .claude/config.yaml)"}}
outputs
{"story_points":{"type":"number","description":"Calculated story points using formula"},"complexity_score":{"type":"number","description":"Complexity assessment (1-5 scale)"},"effort_score":{"type":"number","description":"Effort assessment (1-5 scale)"},"risk_score":{"type":"number","description":"Risk adjustment (0-3 scale)"},"confidence_level":{"type":"string","description":"Estimation confidence (high/medium/low based on clarity and familiarity)"},"estimation_added":{"type":"boolean","description":"Whether estimation block was added to story file"},"split_recommended":{"type":"boolean","description":"Whether story should be split (true if >13 points)"}}
Estimate story points for user stories using a structured, evidence-based formula: Story Points = (Complexity × Effort) + Risk
This provides consistent estimations that help with sprint planning, velocity tracking, and story comparison.
Core Principle: Estimation is not guessing—it's structured analysis of complexity, effort, and risk based on acceptance criteria and technical context.
Prerequisites
Story file exists in .claude/stories/ directory
Story has clear acceptance criteria
Understanding of project tech stack
Access to historical velocity data (optional)
Workflow
1. Load Story Context
Read story file to understand:
User story narrative (As a... I want... So that...)
Acceptance criteria (what needs to be implemented)
Dependencies and technical notes
Current priority level
Load project context:
Team velocity baseline (from .claude/config.yaml)
Tech stack and known patterns
Historical estimation data (if available)
Example story:
**User Story:** As a new user, I want to create an account with email/password
**Acceptance Criteria:**- AC-1: User can enter email and password on signup form
- AC-2: Email validated with Zod
- AC-3: Password hashed with bcrypt
- AC-4: Duplicate emails rejected with 409
- AC-5: Success returns JWT token
- AC-6: User record saved to PostgreSQL
2. Analyze Complexity (1-5 Scale)
Complexity measures technical difficulty and cognitive load (NOT time/effort).
Quick Guide:
1 (Trivial): Single file, copy-paste from existing, no edge cases
Risk: +1
- Team familiar with all tech (Zod, bcrypt, JWT, PostgreSQL)
- Requirements clear and testable
- Minor risk: ensuring proper bcrypt cost and JWT security
See:references/risk-factors.md for detailed risk analysis
