Mapping Webapp

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

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

Prerequisites

1. tree-sitting must be installed (structure is scanned at runtime)
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-webapp/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-webapp/scripts/featuremap.py \
  --app-url https://example.com --codebase /path/to/repo

# Incremental update:
python /mnt/skills/user/mapping-webapp/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
--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 (set in scripts/featuremap.py; that file is the source of truth)	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.)
• Scans the codebase 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 tree-sitting 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. Structure is not persisted alongside it — it is derived on demand:

1. tree-sitting → structure, scanned at runtime
2. mapping-webapp → _FEATURES.md (behavioral)
3. Merge the behavioral layer 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