Composio

Schema Modifiers are a Composio SDK middleware feature for developers building agents with external tools. They sit between your tool registry and the agent, letting you change how a tool appears before the model decides whether and how to use it.

The docs show Python and TypeScript examples, so setup is code-first through the Composio SDK. According to the documentation, this is mainly useful when you want to guide tool usage, reduce mistakes, or adapt a tool schema to a specific workflow.

This is not a standalone agent product; it is a low-level customization layer for Composio tool schemas. It can help when an agent needs clearer instructions or when certain arguments should be required, removed, or given defaults, but it does not itself provide autonomy beyond the surrounding agent setup. The docs also note that if you are building an agent, Composio recommends using sessions instead, since sessions handle tool discovery and execution automatically.

Pricing, deployment model, and model support are not stated on this page. The content also does not mention MCP support or whether the feature is open source. If you are looking for a no-code agent builder or a finished end-user assistant, this is probably not the right fit; it is aimed at developers working directly with tool schemas.