Add "lessons/sprints/sprint-2---contract-validator-plugin-implementation"

lessons%2Fsprints%2Fsprint-2---contract-validator-plugin-implementation.-.md

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+# Sprint 2 - contract-validator Plugin Implementation
+
+## Metadata
+- **Sprint:** Sprint 2 - contract-validator Plugin
+- **Date:** 2026-01-26
+- **Issues:** #185-#193 (9 issues)
+- **Status:** Completed
+
+## Context
+
+Implemented the contract-validator plugin for cross-plugin compatibility validation and CLAUDE.md agent verification. This plugin addresses growing compatibility concerns as the marketplace expands to 12+ plugins.
+
+## What Went Well
+
+### 1. Real Issue Discovery
+The validation tools immediately found a real compatibility issue: `/initial-setup` command is defined by three plugins (projman, data-platform, pr-review). This validates the plugin's usefulness.
+
+### 2. Comprehensive Test Coverage
+Achieved 88% average coverage across core modules:
+- parse_tools.py: 79%
+- validation_tools.py: 96%
+- report_tools.py: 89%
+
+### 3. Regex Pattern Refinement
+Iteratively improved parsing patterns through real-world testing against existing plugins. Key refinements:
+- Agent table parsing required strict `**AgentName**` format to avoid noise
+- Command parsing needed to exclude table separators (`|---|`)
+- Section extraction needed to capture full content until next same-level header
+
+## Challenges & Solutions
+
+### Challenge 1: Plugin Name Matching in Reports
+**Problem:** Report tools couldn't match parsed plugin names (e.g., "Plugin One") to directory names (e.g., "plugin-one") for pairwise validation.
+
+**Solution:** Added `_find_plugin_dir()` method that checks:
+1. Exact lowercase match of directory name
+2. Plugin.json `name` field match
+
+**Prevention:** When designing lookup functions, consider all naming variations upfront.
+
+### Challenge 2: CLAUDE.md Agent Parsing Noise
+**Problem:** Initial regex picked up 62 "agents" including unrelated table rows.
+
+**Solution:** Made pattern more strict:
+- Require `**BoldName**` format in first column
+- Check personality column doesn't contain backticks (tool names)
+- Skip rows where personality contains "---" or looks like header
+
+**Prevention:** Test parsers against real-world documents early, not just synthetic test data.
+
+### Challenge 3: Branch Protection Workflow
+**Problem:** Development branch has push protection, breaking the merge workflow used in Sprint 1.
+
+**Solution:** Each issue gets its own feature branch pushed to remote. PRs created via Gitea web interface.
+
+**Prevention:** Check branch protection settings before starting sprint execution.
+
+## Key Decisions
+
+1. **7 MCP Tools** - Split into parse (2), validate (3), report (2) for clear separation
+2. **Pydantic Models** - Used for all structured data (PluginInterface, ValidationIssue, etc.)
+3. **Dual Report Format** - Markdown for human review, JSON for programmatic use
+4. **Known Data Flow Patterns** - Hardcoded producer/consumer tool lists for data flow validation
+
+## Metrics
+
+| Metric | Value |
+|--------|-------|
+| Issues Completed | 9/9 |
+| MCP Tools | 7 |
+| Commands | 3 |
+| Agents | 2 |
+| Tests | 34 |
+| Coverage | 88% avg |
+| Real Issues Found | 1 (command conflict) |
+
+## Recommendations for Future Sprints
+
+1. **Address Command Conflict** - Create issue to rename `/initial-setup` in data-platform and pr-review to avoid conflict with projman
+2. **Add CI Integration** - Run `/validate-contracts` in CI pipeline before merging plugin changes
+3. **Expand Data Flow Patterns** - Add more producer/consumer tool mappings as plugins grow
+
+## Tags
+- contract-validator
+- mcp-server
+- validation
+- parsing
+- compatibility
+
+
+---
+**Tags:** contract-validator, mcp-server, validation, parsing, sprint-2, v5.0.0