Fence
Keep AI in learning mode. Fence analyzes your TypeScript code, builds a skill profile from what you actually write, and generates a CLAUDE.md that tells Claude to teach — not just produce — the constructs you haven't mastered yet.
How it works
- Run Fence: Scan Workspace in any TypeScript project
- Fence parses every
.ts/.tsx file using a full AST scanner
- It scores your code across 7 dimensions and assigns you a tier (Novice → Expert)
- A
CLAUDE.md is written listing your known and unknown constructs
- Claude reads that file and adjusts — freely using what you know, guiding you through what you don't
- On every subsequent file save, Fence re-scans and keeps the profile current
Skill tiers
| Tier |
Label |
What it signals |
| 1 |
Novice |
Basic types, simple interfaces, typed functions |
| 2 |
Elementary |
Union types, optional chaining, nullish coalescing, destructuring |
| 3 |
Intermediate |
Writing generics, type guards, async/await, higher-order functions |
| 4 |
Advanced |
Conditional types, mapped types, constrained generics, template literal types |
| 5 |
Expert |
Recursive types, variance annotations |
Scoring
Fence measures presence across 7 dimensions (capped at 1 per file to reward breadth, not repetition):
- Idioms (30%) — patterns that show you write idiomatic TypeScript
- Complexity (20%) — use of advanced constructs
- Abstraction (20%) — generic design
- Error handling (15%) — how consistently you handle failure paths
- Modern syntax (15%) — adoption of newer language features
- Anti-pattern penalty —
any, @ts-ignore, unsafe assertions subtract from your score
- Concept fingerprints — bonus detection for combinations like Type Narrowing, Async Mastery, Type Safety, and Generic Design
The final score (1–10) maps to a tier and drives what Claude will and won't generate for you.
Commands
Open the Command Palette (Ctrl+Shift+P / Cmd+Shift+P) and run:
| Command |
What it does |
Fence: Scan Workspace |
Scan all .ts/.tsx files and build your profile |
Fence: Show Profile |
Print your current profile and scores to the Output panel |
Fence: Set Mode |
Switch between learn mode (Claude teaches unknown constructs) and assist mode (Claude only uses known constructs) |
Fence: Reset Profile |
Delete all profile data and start fresh |
Storage
Profile data is saved to three files — profile.json, signals.json, and history.json — in one of three locations, configurable via VS Code settings:
| Setting |
Location |
home (default) |
~/.fence/ |
workspace |
.fence/ in your project root (auto-added to .gitignore) |
custom |
Any absolute path you specify |
Configure under fence.storageLocation and fence.customStoragePath.
Live updates
Fence watches for file saves. When you save a .ts or .tsx file, it debounces for 5 seconds, re-scans that file, re-aggregates the session cache, and rewrites CLAUDE.md — no manual re-scan needed.
Requirements
- VS Code 1.115.0 or higher
- A project containing
.ts or .tsx files
