MCP GDB Server

Instructions

Implementation Reference

• src/index.ts:750-804 (handler)

  The handler function that implements the gdb_set_breakpoint tool. It checks for an active GDB session, executes the 'break' command at the specified location, optionally sets a condition on the breakpoint by parsing the breakpoint number from output, and returns the result or error.

  private async handleGdbSetBreakpoint(args: any) {
    const { sessionId, location, condition } = args;
    
    if (!activeSessions.has(sessionId)) {
      return {
        content: [
          {
            type: 'text',
            text: `No active GDB session with ID: ${sessionId}`
          }
        ],
        isError: true
      };
    }
    
    const session = activeSessions.get(sessionId)!;
    
    try {
      // Set breakpoint
      let command = `break ${location}`;
      const output = await this.executeGdbCommand(session, command);
      
      // Set condition if provided
      let conditionOutput = '';
      if (condition) {
        // Extract breakpoint number from output (assumes format like "Breakpoint 1 at...")
        const match = output.match(/Breakpoint (\d+)/);
        if (match && match[1]) {
          const bpNum = match[1];
          const conditionCommand = `condition ${bpNum} ${condition}`;
          conditionOutput = await this.executeGdbCommand(session, conditionCommand);
        }
      }
      
      return {
        content: [
          {
            type: 'text',
            text: `Breakpoint set at: ${location}${condition ? ` with condition: ${condition}` : ''}\n\nOutput:\n${output}${conditionOutput ? '\n' + conditionOutput : ''}`
          }
        ]
      };
    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : String(error);
      return {
        content: [
          {
            type: 'text',
            text: `Failed to set breakpoint: ${errorMessage}`
          }
        ],
        isError: true
      };
    }
  }

• src/index.ts:183-204 (schema)

  The input schema for the gdb_set_breakpoint tool, defining the required parameters sessionId and location, and optional condition parameter.

  {
    name: 'gdb_set_breakpoint',
    description: 'Set a breakpoint',
    inputSchema: {
      type: 'object',
      properties: {
        sessionId: {
          type: 'string',
          description: 'GDB session ID'
        },
        location: {
          type: 'string',
          description: 'Breakpoint location (e.g., function name, file:line)'
        },
        condition: {
          type: 'string',
          description: 'Breakpoint condition (optional)'
        }
      },
      required: ['sessionId', 'location']
    }
  },

• src/index.ts:373-374 (registration)

  The switch case in the CallToolRequestSchema handler that registers and routes calls to the gdb_set_breakpoint handler function.

  case 'gdb_set_breakpoint':
    return await this.handleGdbSetBreakpoint(request.params.arguments);