Coding

Coding Skill

Provides code writing, execution, and review capabilities using Bun as the runtime.

Operations

Script

Write a TypeScript or JavaScript script to accomplish a task.

Runtime: Bun (prefer Bun built-ins over npm packages) Style: TypeScript with strict types at module boundaries

// Always start with clear intent comment
// Script: <what this does>
// Input: <what it expects>
// Output: <what it produces>

const result = await fetch(url).then(r => r.json());
console.log(JSON.stringify(result, null, 2));

Run

Execute a script or shell command via Bash.

RUN: bun run .system/scripts/<name>.ts
RUN: bun test .system/tests/*.test.ts

Capture output: Always capture stdout/stderr for analysis.

Review

Analyze existing code for issues:

1. Correctness: Does it do what it claims?
2. Safety: Path traversal, injection, unvalidated input?
3. Error handling: Unhandled rejections, silent failures?
4. Performance: Unnecessary awaits in loops, unbounded data reads?
5. Style: Consistent with project conventions?

Update

Modify existing code based on review findings or new requirements. Always:

1. Read the current file
2. Understand the change scope
3. Apply the minimal change that achieves the goal
4. Re-read to verify no unintended changes

Test

Write or run tests to validate behavior.

Framework: Bun's built-in test runner Location: .system/tests/*.test.ts Command: bun test .system/tests/*.test.ts

import { test, expect } from "bun:test";

test("description of behavior", () => {
  expect(actual).toBe(expected);
});

Code Standards

• const over let; no var
• async/await over Promise chains
• Optional chaining (?.) and nullish coalescing (??)
• Explicit error messages at boundaries: throw new Error("X failed: " + detail)
• No hardcoded paths — use relative paths from project root
• No external npm packages unless explicitly approved

Anti-Patterns

• Do not write scripts that delete or overwrite files without reading first
• Do not run commands that affect system state outside .data/ and .system/
• Do not loop on a shell command without a clear exit condition
• Do not import packages not already in package.json
• Do not write // TODO comments in production code — finish the task or raise it explicitly