Mastra•2w ago

How to handle MCP elicitations using MCPClient?

Hey team, I am not able to handle elicitation requests using MCPClient even after sending it from the tool on server. I am initialising the MCPClient as follows:

const servers: Record<string, MastraMCPServerDefinition> = {};
for (const mcp of config.mcps) {
    if (mcp.type === 'http') {
        const serverConfig: MastraMCPServerDefinition = {
            url: new URL(mcp.url),
            timeout: mcp.timeout || 15000,
            capabilities: {
                elicitation: {
                    form: {}
                }
            }
        };
        if (mcp.headers) {
            serverConfig.requestInit = {
                headers: mcp.headers,
            };
        }
        servers[mcp.name] = serverConfig
    } else if (mcp.type === 'command') {
        const serverConfig: MastraMCPServerDefinition = {
            command: mcp.command,
            args: mcp.args,
        }
        servers[mcp.name] = serverConfig
    }
}
this.mcpClient = new MCPClient({ servers: servers, timeout: 15000 });

const servers: Record<string, MastraMCPServerDefinition> = {};
for (const mcp of config.mcps) {
    if (mcp.type === 'http') {
        const serverConfig: MastraMCPServerDefinition = {
            url: new URL(mcp.url),
            timeout: mcp.timeout || 15000,
            capabilities: {
                elicitation: {
                    form: {}
                }
            }
        };
        if (mcp.headers) {
            serverConfig.requestInit = {
                headers: mcp.headers,
            };
        }
        servers[mcp.name] = serverConfig
    } else if (mcp.type === 'command') {
        const serverConfig: MastraMCPServerDefinition = {
            command: mcp.command,
            args: mcp.args,
        }
        servers[mcp.name] = serverConfig
    }
}
this.mcpClient = new MCPClient({ servers: servers, timeout: 15000 });

I adding onRequest handler after getting tools from the server as follow:

if (config.mcps && this.mcpClient) {
    for (const mcp of config.mcps) {
        switch (mcp.name) {
            case 'BASIC_MCP':
                this.logger.info('Setting up elicitation handler for BASIC_MCP');
                await this.mcpClient.elicitation.onRequest('BASIC_MCP', async (request) => {
                    this.logger.info('Elicitation request received for BASIC_MCP: ' + JSON.stringify(request, null, 2));
                    const schema: any = request.requestedSchema;
                    const properties = schema.properties || {};
                    const required = (schema.required as string[]) || [];
                    // send default accept as of now
                    return { action: 'accept', content: {} };
                });
                break;
            default:
                break;
        }
    }
}

if (config.mcps && this.mcpClient) {
    for (const mcp of config.mcps) {
        switch (mcp.name) {
            case 'BASIC_MCP':
                this.logger.info('Setting up elicitation handler for BASIC_MCP');
                await this.mcpClient.elicitation.onRequest('BASIC_MCP', async (request) => {
                    this.logger.info('Elicitation request received for BASIC_MCP: ' + JSON.stringify(request, null, 2));
                    const schema: any = request.requestedSchema;
                    const properties = schema.properties || {};
                    const required = (schema.required as string[]) || [];
                    // send default accept as of now
                    return { action: 'accept', content: {} };
                });
                break;
            default:
                break;
        }
    }
}

(1/2)

6 Replies

OmOP•2w ago

Tool that I have defined on the server side:

case 'REDACTED_TOOL_NAME': {
    server.registerTool(
        'REDACTED_TOOL_NAME',
        {
            title: 'REDACTED_TITLE',
            description: 'REDACTED_DESCRIPTION',
            inputSchema: InputSchema,
        },
        async (params: Input) => {
            const userApproval = await server.server.elicitInput({
                mode: 'form',
                message: 'Are you sure?'
                requestedSchema: {
                    type: 'object',
                    properties: {
                        userConfirmation: {
                            type: 'boolean',
                            title: 'User Confirmation',
                            description: 'Are you sure?'
                        },
                    },
                    required: ['userConfirmation'],
                },
            });

            if (userApproval.action !== 'accept') {
                logger.info('User did not accept!');
                return {
                    content: [
                        {
                            type: 'text' as const,
                            text: 'User did not accept!',
                        },
                    ],
                };
            }

            return {"type":"text", "content":"User has gven confirmation!"}
        },
    );
    break;
}

case 'REDACTED_TOOL_NAME': {
    server.registerTool(
        'REDACTED_TOOL_NAME',
        {
            title: 'REDACTED_TITLE',
            description: 'REDACTED_DESCRIPTION',
            inputSchema: InputSchema,
        },
        async (params: Input) => {
            const userApproval = await server.server.elicitInput({
                mode: 'form',
                message: 'Are you sure?'
                requestedSchema: {
                    type: 'object',
                    properties: {
                        userConfirmation: {
                            type: 'boolean',
                            title: 'User Confirmation',
                            description: 'Are you sure?'
                        },
                    },
                    required: ['userConfirmation'],
                },
            });

            if (userApproval.action !== 'accept') {
                logger.info('User did not accept!');
                return {
                    content: [
                        {
                            type: 'text' as const,
                            text: 'User did not accept!',
                        },
                    ],
                };
            }

            return {"type":"text", "content":"User has gven confirmation!"}
        },
    );
    break;
}

What am I missing here? (2/2) And yes the error I get when I try to do this is:

McpError: MCP error -32001: Request timed out

McpError: MCP error -32001: Request timed out

from the MCP Server

Failed tool execution

Failed tool execution

from agents backend Dependencies I am using: "@mastra/core": "^0.24.1", "@mastra/mcp": "^0.14.4", "@modelcontextprotocol/sdk": "^1.22.0" I can see my MCP sever is trying to elicit the user input but same is not being accepted by the MCPClient

Mastra Triager•2w ago

📝 Created GitHub issue: https://github.com/mastra-ai/mastra/issues/10668 🔍 If you're experiencing an error, please provide a minimal reproducible example whenever possible to help us resolve it quickly. 🙏 Thank you for helping us improve Mastra!

Abhi Aiyer•2w ago

Hey @Om ill take a look! Hmm i tried reproducing, and while i dont get Request timed out i do get an elicitation failed error Let me post my repro and the fixed version

Abhi Aiyer•2w ago

Broken: https://gist.github.com/abhiaiyer91/4457159c0a04b0e8064146060783cfd3 Fixed: https://gist.github.com/abhiaiyer91/5bf4569ab97fe9b0aeb5cb8c79e625c3

Gist

elicitation-broken.ts

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Gist

elicitation-fixed.ts

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OmOP•2w ago

@Abhi Aiyer thankyou so much for your efforts. Appreciated, but the issue was from my side. The way I was orchestrating MCP server was wrong so I fixed that and it worked perfectly. Sorry for the trouble tho 😬 Thankyou!

Abhi Aiyer•2w ago

That’s great to hear! No problem!

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How to handle MCP elicitations using MCPClient?

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