Recipe (Wield)
In Wield, a recipe is a small public JSON file. It describes the requests a website's own pages make: their inputs, their steps and how to extract the result. The Wield extension runs the recipe in the user's browser, so the site sees the session the user already has. Recipes are data, not code, and the registry signs each one with Ed25519.
How a recipe works
A recipe has a fixed set of parts:
| Part | What it holds |
|---|---|
site | The site id, the origin the run uses, and the only origins it may call |
params | A JSON Schema for the inputs. wield-mcp validates them before anything is sent |
steps | Up to 12 requests. Independent GET steps run in parallel |
extract and output | What the agent gets back, with a schema |
verify | Example params and checks that test the recipe against the live site |
effect | read or write. Writes need the user's Allow |
Requests use the browser's Fetch API, and by default they include the site's cookies. Wield does not follow a redirect to a host the recipe does not list.
Why it matters for AI agents
A recipe turns a website into a tool with a fixed input and output shape. Because it names its origins and limits, an agent can review what it may do before it runs. The agent never gets to send requests anywhere else.
Wield and recipes
Every recipe is versioned. Older versions stay beside the current one. Public read recipes that can run from a server are health-checked daily. A failing recipe is marked degraded, and wield-mcp falls back to the last good version.
Recipes are signed with Ed25519. wield-mcp and the extension refuse unsigned or changed recipes. The registry lists 29 sites as of 7 November 2026. Anyone can request a site at /sites.
Related terms
FAQ
What is inside a recipe?
A recipe is one JSON file. Its id has the form site/name, such as bahn.de/search-connections. It has a schema, an id, a version, the site block, the params schema, the steps, the output and the verify block. The steps can use earlier results through templates, and the output uses JMESPath to shape the result.
Who can write recipes?
Anyone can request a site from the agent or at /sites. Making a recipe for a new site uses the Wield recorder. It captures the network calls of one task in your browser and strips cookies, auth headers, tokens and body values on your device. The hosted recipe builder drafts a recipe from that trace, and your own browser verifies it live. Recording and the builder are paid-plan features. A verified recipe is published privately or, after review, publicly.
Sources
- Fetch API (MDN)developer.mozilla.org