coder

import { createRuntime } from '@agentskit/runtime'
import { coder } from '@agentskit/skills'
import { filesystem, shell } from '@agentskit/tools'

const runtime = createRuntime({
  adapter,
  skills: [coder],
  tools: [
    ...filesystem({ basePath: './workspace' }),
    shell({ allowed: ['pnpm', 'node', 'git'] }),
  ],
})

When to reach for it

• Agent needs to write real code (not snippets).
• Multi-file edits, package additions, refactors.
• Works best when paired with a sandboxed filesystem.

Behavior

• Reads before writing — lists files, opens existing implementations.
• Writes TypeScript strict; prefers named exports.
• Tests alongside code (Vitest conventions).
• Avoids unsafe casts, runs type-check before declaring done.

Tools it expects

Compose

Pair with codeReviewer for a self-review pass, or delegate to the critic skill to stress-test output.

Safety

Always sandbox with filesystem({ basePath }) and shell({ allowed }) — coder writes files. For mutation flows use mandatory sandbox.

Related

• Skills overview · codeReviewer
• Recipe: code-reviewer