Function: error()

function error(message, code?): ToolResponse;

Defined in: packages/core/src/core/response.ts:161

Create an error response.

Sets isError: true so the MCP client and LLM recognize the failure. The LLM will typically retry or ask the user for clarification.

Parameters

Parameter	Type	Description
message	string	Human-readable error description
code?	ErrorCode	-

Returns

ToolResponse

A ToolResponse with isError: true

Example

// Simple error
return error('Project not found');

// Contextual error
return error(`User "${userId}" does not have access to workspace "${wsId}"`);

// In a handler with early return
handler: async (ctx, args) => {
    const project = await ctx.db.projects.findUnique(args.id);
    if (!project) return error(`Project "${args.id}" not found`);
    return success(project);
}

See

• required for missing field errors
• success for success responses