callscriptBLOCK

Code Mode, without the sandbox.

The model writes JavaScript; callscript parses it into a JSON plan instead of executing it. Plans validate before they run, suspend and resume across processes, and keep intermediate results addressable so steps aren't re-executed to recover their output. With no sandbox and no separate runtime, the only thing the code can execute is your tools.

Install

npm install callscript

Two small runtime dependencies (acorn, zod), no sandbox, no service: the engine is a library that runs wherever your JS runs. The adapter's peer (ai) is optional and only needed by its own entrypoint.

Quick start

Mount your AI SDK tools on an engine and hand the model the ready-made tools - execute runs the script it authors; search and describe let it discover mounted tools without carrying every definition in its prompt:

import { generateText } from "ai";
import { callscript } from "callscript";
import { toAISDKTools, fromAISDKTools } from "callscript/ai-sdk";

const engine = callscript({
tools: fromAISDKTools(tools, { namespace: "github" }),
});

await generateText({
model: "anthropic/claude-sonnet-5",
prompt: "Close every stale open issue in the 'api' repo.",
tools: toAISDKTools(engine), // execute + search + describe
});

Why

Classic tool calling has a shape problem: one call per model round-trip. Every intermediate result travels back through the context window just so the model can look at it and decide the next call: slow