Tools

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Built-in Tools

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Tool Details

• cli — Runs shell commands. Timeout is 120s by default (configurable). Output is capped at ~100 KB (stdout + stderr combined).
• read — Reads file contents. Encoding utf-8 (binary files return a placeholder message). Use offset and limit for large files (offset = start line, limit = number of lines) — it won’t load the whole thing at once.
• write — Creates or overwrites files. Parent directories are created automatically.
• memory — Loads and saves to memory/MEMORY.md. load returns MEMORY.md contents; save appends + git commits (every save is a git commit — fully versioned). Auto-archives when max_lines exceeded to memory/archive/<YYYY-MM>.md.

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Declarative Tools

# tools/lookup-account.yaml
name: lookup-account
description: Look up account details by customer ID
input_schema:
  properties:
    customer_id:
      type: string
      description: The customer ID
  required: [customer_id]
implementation:
  script: scripts/lookup.sh
  runtime: sh

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Tool Allowlists and Denylists

// SDK — allowlist or denylist per query
for await (const msg of query({
  prompt: "...",
  allowedTools: ["read", "cli"],
  disallowedTools: ["write"],
})) { /* ... */ }