Agent skill
analyze-gaps
Analyze gaps between codebase and PRD documentation, generate discrepancies report. Use this skill when you need to sync documentation with implementation, find undocumented features, or identify unbuilt requirements.
Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/documents/analyze-gaps
SKILL.md
Analyze Gaps
Compares codebase implementation against PRD documents to identify discrepancies and generate a structured report.
When to Use
- Before updating PRD docs to reflect implementation
- Before creating new tickets for unbuilt features
- When codebase and documentation may be out of sync
- As first step in sync-prd or sync-planning workflows
Workflow
Step 1: Fresh Start
Remove existing discrepancies report to start fresh:
rm -f docs/1-prd/99-discrepancies.md
Initialize new report with header:
# Discrepancies Report (In Progress)
Generated: {date}
Focus: {area or 'all'}
Status: ANALYZING
## Notes
(Working notes captured during analysis)
Step 2: Analyze Codebase
Explore the project structure to understand current implementation:
- Explore project structure (src/, lib/, etc.)
- Identify main features and modules implemented
- Note APIs, data models, integrations present
- Document patterns and conventions used
Update 99-discrepancies.md with findings as you go:
- Add discovered modules/features under Notes
- Track code paths and entry points
- Note patterns that may not be in PRD
If a focus area is specified, concentrate analysis on that area.
Step 3: Analyze PRD
Read all PRD documents under docs/1-prd/ (excluding 99-discrepancies.md):
- List all documented features and requirements
- Note expected behaviors and specifications
- Identify assumptions or constraints mentioned
Update 99-discrepancies.md iteratively:
- Cross-reference PRD items against codebase notes
- Mark items as you compare them
- Add preliminary gap observations
Step 4: Find Gaps
Compare codebase with PRD to identify discrepancies:
| Gap Type | Description | Action Needed |
|---|---|---|
IMPLEMENTED_NOT_DOCUMENTED |
Feature exists in code but not in PRD | Update PRD |
DOCUMENTED_NOT_IMPLEMENTED |
PRD describes feature not yet built | Create ticket |
DIVERGED |
Implementation differs from PRD spec | Align (either direction) |
OUTDATED |
PRD describes old/changed behavior | Update PRD |
Update 99-discrepancies.md as gaps are found:
- Categorize each gap by type
- Add code location and PRD file references
- Note specific discrepancy details
- Record recommended action
Step 5: Finalize Report
Transform working notes in 99-discrepancies.md into final structured report.
Update status from ANALYZING to COMPLETE and reorganize content:
# Discrepancies Report
Generated: {date}
Focus: {area or 'all'}
Status: COMPLETE
## Summary
- Total gaps: N
- IMPLEMENTED_NOT_DOCUMENTED: N
- DOCUMENTED_NOT_IMPLEMENTED: N
- DIVERGED: N
- OUTDATED: N
## IMPLEMENTED_NOT_DOCUMENTED
(Features in code but not in PRD - need PRD update)
### Feature Name
- **Code location:** path/to/code
- **Details:** description
- **Recommended action:** Add to PRD
## DOCUMENTED_NOT_IMPLEMENTED
(PRD features not yet built - need tickets)
### Feature Name
- **PRD file:** docs/1-prd/feature.md
- **Details:** description
- **Recommended action:** Create ticket T0000N
## DIVERGED
(Implementation differs from spec - need alignment)
### Feature Name
- **Code location:** path/to/code
- **PRD file:** docs/1-prd/feature.md
- **Details:** how they differ
- **Recommended action:** Update PRD or implementation
## OUTDATED
(PRD describes old behavior - need PRD update)
### Feature Name
- **PRD file:** docs/1-prd/feature.md
- **Details:** what changed
- **Recommended action:** Update PRD
Output
After running this skill:
- Previous
docs/1-prd/99-discrepancies.mdis removed (fresh start) - New report is built iteratively during analysis
- Final report has
Status: COMPLETEwhen done - Report is ready for consumption by:
sync-prdskill (handles IMPLEMENTED_NOT_DOCUMENTED, DIVERGED, OUTDATED)sync-planningskill (handles DOCUMENTED_NOT_IMPLEMENTED)
Intermediate States
The report transitions through states:
Status: ANALYZING- Working notes being capturedStatus: COMPLETE- Final structured report ready
Example Usage
User: Analyze gaps in the authentication module
Assistant: [Uses analyze-gaps skill with focus_area="auth"]
User: Find discrepancies between code and PRD
Assistant: [Uses analyze-gaps skill]
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