mapping-features

name	mapping-features
description	Generate behavioral/feature documentation for web apps using code-first analysis. Reads source code and _MAP.md files to produce _FEATURES.md, with optional visual verification via browser automation. Companion to mapping-codebases. Use when documenting app behavior, creating feature inventories, generating behavioral ground truth for agents, or before modifying UI code. Triggers on "map features", "document app behavior", "feature inventory", "what does this app do".
metadata	{"version":"0.3.0"}

Mapping Features

Generate _FEATURES.md files documenting what a web app does — screens, flows, states, behavioral invariants. Companion to mapping-codebases which documents code structure.

v0.3.0: Code-first architecture. The code IS the ground truth; screenshots are supplementary verification.

Prerequisites

1. mapping-codebases must have run first (_MAP.md files exist)
2. Claude API key available (via api-credentials skill or ANTHROPIC_API_KEY env var)
3. Optional: webctl for visual verification (not required for --code-only)

Usage

# Code-only analysis (no browser needed):
python /mnt/skills/user/mapping-features/scripts/featuremap.py \
  --app-url https://example.com --codebase /path/to/repo --code-only

# Full pipeline (code analysis + selective visual verification):
python /mnt/skills/user/mapping-features/scripts/featuremap.py \
  --app-url https://example.com --codebase /path/to/repo

# Incremental update:
python /mnt/skills/user/mapping-features/scripts/featuremap.py \
  --app-url https://example.com --codebase . --incremental

Options

Flag	Default	Description
--app-url	required	Base URL of the web app
--codebase	required	Path to repo root (must have _MAP.md files)
--output	<codebase>/_FEATURES.md	Output path
--max-pages	100	Cap on pages to discover
--code-only	false	Skip all vision — code analysis only
--verify-only	false	Only run vision on already-analyzed pages
--batch-size	auto	Pages per batch (auto-detected from environment)
--incremental	false	Only re-process changed pages
--viewport	1280x720	Screenshot viewport (WxH)
--routes	none	Comma-separated routes or path to routes file
--screenshots-dir	<codebase>/screenshots	Where to store PNGs
--model	claude-sonnet-4-6	Claude model for analysis/vision
--dry-run / -n	false	Discover only, print sitemap

Architecture: Code-First Pipeline

Phase 1: DISCOVER

Discovers pages from code structure, not browser crawling:

• Scans for HTML files (static sites)
• Detects framework routing conventions (Next.js, SvelteKit, etc.)
• Parses _MAP.md for page references
• Supplements with --routes for manual seeding

No browser required for discovery.

Phase 2: ANALYZE

Reads source code for each discovered page and uses Claude API (text, not vision) to generate behavioral descriptions:

• Finds relevant source files (HTML + referenced JS/CSS)
• Includes _MAP.md excerpts for code context
• Produces: what the user sees, interactions, invariants, code references

Code-derived descriptions are usable standalone. Vision is enrichment, not requirement.

Phase 3: VERIFY (optional)

Selective visual verification for pages where it adds value:

• Skips error pages (404, 500), gated pages, redirects
• Captures screenshots + accessibility trees via webctl
• Sends to Claude vision API to verify/enrich code descriptions
• Falls back to code description if vision fails

Skipped entirely with --code-only. Run only this phase with --verify-only.

Phase 4: ASSEMBLE

Compiles all descriptions into _FEATURES.md:

• Source badges indicate code-analyzed vs visually-verified
• Screenshot references only for verified pages
• Status summary with breakdown by source

Environment-Adaptive Batching

The skill auto-detects the runtime environment and adjusts batch size:

Environment	Batch Size	Notes
Claude.ai container	4 pages	Short bash timeouts
Claude Code on Web	12 pages	Longer execution windows
Local CLI	Unbatched	Full control

Override with --batch-size N.

Progress is checkpointed after each batch via _FEATURES_MANIFEST.json, so work survives if a conversation ends mid-pipeline.

Incremental Mode

Each run stores page hashes and descriptions in _FEATURES_MANIFEST.json. With --incremental:

• Code analysis: skips pages with existing descriptions
• Visual verification: skips pages with unchanged screenshots
• Descriptions from previous runs are preserved and merged

Auth / Gated Pages

Pages requiring authentication are detected during verification (redirect detection + text heuristics) and marked GATED. The skill generates step-by-step manual capture instructions in GATED_PAGES.md.

Output Format

# _FEATURES.md — App Name
Generated: 2026-03-22T12:00:00+0000
App URL: https://example.com

## Feature Inventory

### Status Summary
- **Documented:** 45 pages
  - Code-analyzed: 40
  - Visually verified: 5
- **Gated (auth required):** 2 pages

### Page Title (`/route`)
> *Derived from source code analysis*

**What the user sees:** Prose description from code analysis.

**Interactions:**
- Button "X" → does Y

**Invariants:**
- Rule 1

**Code:** `src/page.html` :1

---

Relationship to CLAUDE.md

_FEATURES.md is the behavioral source of truth. Combined with _MAP.md (structural):

1. mapping-codebases → _MAP.md (structural)
2. mapping-features → _FEATURES.md (behavioral)
3. Merge both into CLAUDE.md architecture/concepts sections

Limitations

• Code analysis requires Claude API calls (tokens)
• Visual verification requires webctl + a running app instance
• SPAs with client-side routing may need --routes flag
• Auth-gated pages require human intervention for visual verification
• Code analysis quality depends on source code readability