Execution

Agent Skills can bundle scripts under scripts/. An agent runs them in one of two ways:

When skills are files in a Workspace, a script is a file the agent can run like any other. Give the Workspace a backend, and Think adds the exec tool. Refer to Computer for the setup.

Activating a skill returns its folder as location, for example /workspace/.agents/skills/release-notes. With the JavaScript backend, the skill's instructions can tell the model to run a script from that folder:

export { default } from "./scripts/format-release-notes.js";

The script exports a default async function. It receives the input that the model passes to exec, and can use node:fs to read the Workspace:

import { readdir } from "node:fs/promises";

export default async function (input) {
	const entries = await readdir(input.root ?? "/workspace");
	return { count: entries.length };
}

For skills that do not live in a Workspace, skills.runner() runs bundled scripts in a Dynamic Worker and adds the run_skill_script tool. It needs a Worker Loader binding:

{
	"worker_loaders": [{ "binding": "LOADER" }],
}

[[worker_loaders]]
binding = "LOADER"

Return the runner from getSkillScriptRunner():

import { Think, skills } from "@cloudflare/think";

export class MyAgent extends Think {
	getSkills() {
		return [skills.r2(this.env.SKILLS_BUCKET, { prefix: "skills/" })];
	}

	getSkillScriptRunner() {
		return skills.runner({ loader: this.env.LOADER });
	}
}

import { Think, skills } from "@cloudflare/think";

export class MyAgent extends Think<Env> {
	getSkills() {
		return [skills.r2(this.env.SKILLS_BUCKET, { prefix: "skills/" })];
	}

	getSkillScriptRunner() {
		return skills.runner({ loader: this.env.LOADER });
	}
}

Outside Think, import the runner from agents/skills/runner. It is a separate entry point because it loads just-bash and Code Mode:

import { runner } from "agents/skills/runner";

const scriptRunner = runner({ loader: env.LOADER });

import { runner } from "agents/skills/runner";

const scriptRunner = runner({ loader: env.LOADER });

The runner runs JavaScript, Python, and Bash scripts under scripts/. Python runs as a Python Dynamic Worker, and Bash runs through just-bash. There is no bundler at runtime: a JavaScript script must be one self-contained module. Compile TypeScript and multi-file scripts, for example with esbuild, before you store the skill.

JavaScript scripts export a default function that takes the input and a context object:

export default async function run(input, ctx) {
	const guide = ctx.files["references/style-guide.md"]; // bundled text resources
	const docs = await ctx.workspace.readFile("README.md"); // gated by permission
	const summary = await ctx.tools.call("summarize", { input }); // explicit tools
	await ctx.output.writeFile("notes.md", summary); // scratch artifact
	return { ok: true };
}

ctx is typed as SkillRunContext and contains:

Python and Bash scripts use files instead of a context object:

• /input.json holds the input.
• /context.json holds the skill metadata.
• /skill holds SKILL.md and the skill's resources.
• Files written to /output are returned to the model.

Python scripts can also define def run(input, ctx).

Scripts get no network access and no tools unless you grant them. Relative paths in ctx.workspace resolve against /workspace.

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