ARBuilder

Instructions

Implementation Reference

• src/mcp/tools/ask_bridging.py:119-232 (handler)

  The 'execute' method of AskBridgingTool handles the core logic for answering bridging questions, using a knowledge base and optional RAG context.

  def execute(self, **kwargs) -> dict[str, Any]:
      """Answer a bridging question."""
      question = kwargs.get("question", "").strip()
      include_code = kwargs.get("include_code_example", False)
  
      if not question:
          return {"error": "Question is required and cannot be empty"}
  
      # Normalize question
      q_lower = question.lower()
  
      # Try to match against knowledge base
      answer_parts = []
      relevant_topics = []
  
      # Check for ETH-related questions
      if "eth" in q_lower and ("deposit" in q_lower or "bridge" in q_lower or "withdraw" in q_lower):
          if "withdraw" in q_lower or ("l1" in q_lower and "from l2" in q_lower):
              relevant_topics.append("eth_withdraw")
          else:
              relevant_topics.append("eth_deposit")
  
      # Check for token/ERC20 questions
      if "token" in q_lower or "erc20" in q_lower:
          if "withdraw" in q_lower:
              relevant_topics.append("erc20_withdraw")
          else:
              relevant_topics.append("erc20_deposit")
  
      # Check for retryable ticket questions
      if "retryable" in q_lower or "ticket" in q_lower:
          relevant_topics.append("retryable_tickets")
  
      # Check for messaging questions
      if "message" in q_lower or "messaging" in q_lower:
          if "l2 to l1" in q_lower or "l2->l1" in q_lower or "withdraw" in q_lower:
              relevant_topics.append("l2_to_l1_messaging")
          else:
              relevant_topics.append("l1_to_l2_messaging")
  
      # Check for L3/Orbit questions
      if "l3" in q_lower or "orbit" in q_lower:
          relevant_topics.append("l1_l3_bridging")
  
      # Check for gas token questions
      if "gas token" in q_lower or "custom gas" in q_lower:
          relevant_topics.append("custom_gas_token")
  
      # Check for timing questions
      if "how long" in q_lower or "time" in q_lower or "when" in q_lower:
          if "withdraw" in q_lower:
              relevant_topics.extend(["eth_withdraw", "l2_to_l1_messaging"])
          else:
              relevant_topics.append("eth_deposit")
  
      # Build answer from relevant topics
      if relevant_topics:
          for topic in set(relevant_topics):
              if topic in BRIDGING_KNOWLEDGE:
                  info = BRIDGING_KNOWLEDGE[topic]
                  answer_parts.append(f"## {topic.replace('_', ' ').title()}")
                  for key, value in info.items():
                      if isinstance(value, list):
                          answer_parts.append(f"**{key.replace('_', ' ').title()}:**")
                          for item in value:
                              answer_parts.append(f"  - {item}")
                      else:
                          answer_parts.append(f"**{key.replace('_', ' ').title()}:** {value}")
                  answer_parts.append("")
  
      # Try RAG context if available
      rag_context = ""
      if self.context_tool:
          try:
              # Use execute() method with custom boosting for bridging/SDK content
              ctx_result = self.context_tool.execute(
                  query=question,
                  n_results=3,
                  rerank=True,
                  category_boosts={
                      "arbitrum_docs": 1.3,    
                      "arbitrum_sdk": 1.5,    
                      "orbit_sdk": 1.0,       
                      "stylus": 0.8,          
                  },
              )
              if ctx_result.get("contexts"):
                  rag_context = "\n\n".join(
                      c.get("content", "") for c in ctx_result["contexts"][:2]
                  )
          except Exception:
              pass  # RAG is optional
  
      # Build final answer
      if answer_parts:
          answer = "\n".join(answer_parts)
      else:
          # Generic answer for unmatched questions
          answer = self._get_generic_answer(question)
  
      result = {
          "answer": answer,
          "topics": list(set(relevant_topics)) if relevant_topics else ["general"],
          "references": self._get_references(relevant_topics),
      }
  
      if include_code:
          result["code_example"] = self._get_code_example(relevant_topics)
  
      if rag_context:
          result["additional_context"] = rag_context[:1000]
  
      return result

• src/mcp/server.py:885-885 (registration)

  Registration of the ask_bridging tool in the MCP server.

  "ask_bridging": AskBridgingTool(context_tool=self.context_tool),

• src/mcp/tools/ask_bridging.py:98-112 (schema)

  Input schema for the ask_bridging tool.

  input_schema = {
      "type": "object",
      "properties": {
          "question": {
              "type": "string",
              "description": "Question about Arbitrum bridging or messaging",
          },
          "include_code_example": {
              "type": "boolean",
              "description": "Include a code example in the answer if relevant",
              "default": False,
          },
      },
      "required": ["question"],
  }