Cerebra Legal MCP Server

Instructions

Implementation Reference

• src/index.ts:520-600 (handler)

  The primary handler function that implements the core logic for the 'legal_think' tool. It validates input, detects the legal domain, manages thought history, provides guidance/templates as needed, formats and logs the thought, and returns a structured JSON response.

  function processLegalThink(input: unknown): { content: Array<{ type: string; text: string }>; isError?: boolean } {
    try {
      const data = input as Record<string, unknown>;
      
      // Validate input
      if (!data.thought || typeof data.thought !== 'string') {
        throw new Error('Invalid thought: must be a string');
      }
      if (!data.thoughtNumber || typeof data.thoughtNumber !== 'number') {
        throw new Error('Invalid thoughtNumber: must be a number');
      }
      if (!data.totalThoughts || typeof data.totalThoughts !== 'number') {
        throw new Error('Invalid totalThoughts: must be a number');
      }
      if (typeof data.nextThoughtNeeded !== 'boolean') {
        throw new Error('Invalid nextThoughtNeeded: must be a boolean');
      }
      
      // Detect domain
      const domain = data.category as string || detectDomain(data.thought as string);
      
      // Add to thought history
      thoughtHistory.push({
        ...data,
        domain,
        timestamp: new Date()
      });
      
      // Determine if guidance or templates should be provided
      let guidance = undefined;
      let template = undefined;
      
      if (data.requestGuidance || data.thoughtNumber === 1) {
        guidance = domainGuidance[domain] || domainGuidance["legal_reasoning"];
      }
      
      if (data.requestTemplate || data.thoughtNumber === 1) {
        template = domainTemplates[domain] || domainTemplates["legal_reasoning"];
      }
      
      // Format the thought for logging
      const formattedThought = formatThought(
        data.thought as string,
        domain,
        data.thoughtNumber as number,
        data.totalThoughts as number,
        data.isRevision as boolean,
        data.revisesThoughtNumber as number
      );
      
      // Log the formatted thought
      console.error(formattedThought);
      
      // Prepare response
      return {
        content: [{
          type: "text",
          text: JSON.stringify({
            thoughtNumber: data.thoughtNumber,
            totalThoughts: data.totalThoughts,
            nextThoughtNeeded: data.nextThoughtNeeded,
            detectedDomain: domain,
            guidance,
            template,
            thoughtHistoryLength: thoughtHistory.length
          }, null, 2)
        }]
      };
    } catch (error) {
      return {
        content: [{
          type: "text",
          text: JSON.stringify({
            error: error instanceof Error ? error.message : String(error),
            status: 'failed'
          }, null, 2)
        }],
        isError: true
      };
    }
  }

• src/index.ts:32-91 (schema)

  The input schema definition for the legal_think tool, specifying properties, types, descriptions, and required fields for input validation.

  inputSchema: {
    type: "object",
    properties: {
      thought: {
        type: "string",
        description: "The main legal reasoning content"
      },
      category: {
        type: "string",
        enum: [
          "analysis", 
          "planning", 
          "verification", 
          "legal_reasoning", 
          "ansc_contestation",
          "consumer_protection",
          "contract_analysis"
        ],
        description: "Category of legal reasoning (optional, will be auto-detected if not provided)"
      },
      references: {
        type: "array",
        items: {
          type: "string"
        },
        description: "References to laws, regulations, precedents, or previous thoughts (optional)"
      },
      isRevision: {
        type: "boolean",
        description: "Whether this thought revises a previous legal reasoning (optional)"
      },
      revisesThoughtNumber: {
        type: "integer",
        description: "The thought number being revised (if isRevision is true)"
      },
      requestGuidance: {
        type: "boolean",
        description: "Set to true to receive domain-specific legal guidance"
      },
      requestTemplate: {
        type: "boolean",
        description: "Set to true to receive a template for this type of legal reasoning"
      },
      thoughtNumber: {
        type: "integer",
        description: "Current thought number",
        minimum: 1
      },
      totalThoughts: {
        type: "integer",
        description: "Estimated total thoughts needed",
        minimum: 1
      },
      nextThoughtNeeded: {
        type: "boolean",
        description: "Whether another thought step is needed"
      }
    },
    required: ["thought", "thoughtNumber", "totalThoughts", "nextThoughtNeeded"]
  }

• src/index.ts:15-92 (registration)

  The Tool object definition for 'legal_think', including name, description, and input schema, used for registration.

  const LEGAL_THINK_TOOL: Tool = {
    name: "legal_think",
    description: `A powerful tool for structured legal reasoning that helps analyze complex legal issues.
  This tool provides domain-specific guidance and templates for different legal areas including ANSC contestations, consumer protection, and contract analysis.
  
  When to use this tool:
  - Breaking down complex legal problems into structured steps
  - Analyzing legal requirements and compliance
  - Verifying that all elements of a legal test are addressed
  - Building comprehensive legal arguments with proper citations
  
  Key features:
  - Automatic detection of legal domains
  - Domain-specific guidance and templates
  - Support for legal citations and references
  - Revision capabilities for refining legal arguments
  - Thought quality feedback`,
    inputSchema: {
      type: "object",
      properties: {
        thought: {
          type: "string",
          description: "The main legal reasoning content"
        },
        category: {
          type: "string",
          enum: [
            "analysis", 
            "planning", 
            "verification", 
            "legal_reasoning", 
            "ansc_contestation",
            "consumer_protection",
            "contract_analysis"
          ],
          description: "Category of legal reasoning (optional, will be auto-detected if not provided)"
        },
        references: {
          type: "array",
          items: {
            type: "string"
          },
          description: "References to laws, regulations, precedents, or previous thoughts (optional)"
        },
        isRevision: {
          type: "boolean",
          description: "Whether this thought revises a previous legal reasoning (optional)"
        },
        revisesThoughtNumber: {
          type: "integer",
          description: "The thought number being revised (if isRevision is true)"
        },
        requestGuidance: {
          type: "boolean",
          description: "Set to true to receive domain-specific legal guidance"
        },
        requestTemplate: {
          type: "boolean",
          description: "Set to true to receive a template for this type of legal reasoning"
        },
        thoughtNumber: {
          type: "integer",
          description: "Current thought number",
          minimum: 1
        },
        totalThoughts: {
          type: "integer",
          description: "Estimated total thoughts needed",
          minimum: 1
        },
        nextThoughtNeeded: {
          type: "boolean",
          description: "Whether another thought step is needed"
        }
      },
      required: ["thought", "thoughtNumber", "totalThoughts", "nextThoughtNeeded"]
    }
  };

• src/index.ts:821-827 (registration)

  Registration of the legal_think tool in the MCP listTools request handler.

  server.setRequestHandler(ListToolsRequestSchema, async () => ({
    tools: [
      LEGAL_THINK_TOOL,
      LEGAL_ASK_FOLLOWUP_QUESTION_TOOL,
      LEGAL_ATTEMPT_COMPLETION_TOOL
    ],
  }));

• src/index.ts:832-834 (registration)

  Dispatch/registration of the legal_think tool handler in the MCP callTool request handler.

  if (request.params.name === "legal_think") {
    return processLegalThink(request.params.arguments);
  }