chainlist-mcp

Instructions

Retrieve information about blockchains matching a keyword (case-insensitive partial match), returned as Markdown.

**Parameters**:
- `keyword` (string): The keyword or partial name of the blockchain to search for (e.g., 'eth' for Ethereum).
- `limit` (integer, optional): Maximum number of matching chains to return (default: 5).

**Returns**:
- A Markdown-formatted string listing up to `limit` matching chains with their details (Name, Chain ID, Native Currency, TVL, RPC Endpoints, Explorers) or an error message if no chains are found.

Implementation Reference

• main.py:83-110 (handler)

  The handler function decorated with @mcp.tool(), implementing the core logic: fetches chains, filters by keyword using regex (case-insensitive), limits results, formats output as Markdown using format_chain_as_markdown.

  @mcp.tool()
  async def getChainsByKeyword(keyword: str, limit: int = 5) -> str:
      """
      Retrieve information about blockchains matching a keyword (case-insensitive partial match), returned as Markdown.
  
      **Parameters**:
      - `keyword` (string): The keyword or partial name of the blockchain to search for (e.g., 'eth' for Ethereum).
      - `limit` (integer, optional): Maximum number of matching chains to return (default: 5).
  
      **Returns**:
      - A Markdown-formatted string listing up to `limit` matching chains with their details (Name, Chain ID, Native Currency, TVL, RPC Endpoints, Explorers) or an error message if no chains are found.
      """
      chains = await fetch_chain_data()
      pattern = re.escape(keyword.strip())
      matches: List[Dict[str, Any]] = []
      
      for chain in chains:
          chain_name = chain.get("name", "")
          if re.search(pattern, chain_name, re.IGNORECASE):
              matches.append(chain)
      
      if matches:
          output = "**Matching Chains**\n\n"
          # Apply limit to matches
          for i, chain in enumerate(matches[:limit], 1):
              output += f"### Chain {i}\n{format_chain_as_markdown(chain)}\n"
          return output
      return f"**Error**: No chains found matching keyword '{keyword}'"

• main.py:14-22 (helper)

  Helper function to fetch and cache the chain data from the Chainlist API, used by getChainsByKeyword.

  async def fetch_chain_data() -> list[Dict[str, Any]]:
      """Fetch and cache chain data from Chainlist API."""
      global chain_data
      if chain_data is None:
          async with httpx.AsyncClient() as client:
              response = await client.get("https://chainlist.org/rpcs.json")
              response.raise_for_status()
              chain_data = response.json()
      return chain_data

• main.py:24-64 (helper)

  Helper function to format a single chain's details as Markdown with tables for RPCs and explorers, called by getChainsByKeyword.

  def format_chain_as_markdown(chain: Dict[str, Any]) -> str:
      """
      Format a single chain's details as Markdown, extracting specified fields with RPC and Explorers as tables.
      """
      # Extract required fields
      name = chain.get('name', 'N/A')
      chain_id = chain.get('chainId', 'N/A')
      native_currency = chain.get('nativeCurrency', {})
      tvl = chain.get('tvl', 'N/A')
      rpc_list = chain.get('rpc', [])
      explorers_list = chain.get('explorers', [])
  
      # Format native currency
      currency_info = f"{native_currency.get('name', 'N/A')} ({native_currency.get('symbol', 'N/A')}, {native_currency.get('decimals', 'N/A')} decimals)" if native_currency else 'N/A'
  
      # Format RPC list as a table
      rpc_data = [[rpc.get('url', 'N/A'), rpc.get('tracking', 'N/A')] for rpc in rpc_list]
      rpc_output = "**RPC Endpoints**:\n"
      if rpc_data:
          rpc_output += tabulate(rpc_data, headers=["URL", "Tracking"], tablefmt="pipe")
      else:
          rpc_output += "None"
  
      # Format explorers list as a table
      explorers_data = [[explorer.get('name', 'N/A'), explorer.get('url', 'N/A'), explorer.get('standard', 'N/A')] for explorer in explorers_list]
      explorers_output = "**Explorers**:\n"
      if explorers_data:
          explorers_output += tabulate(explorers_data, headers=["Name", "URL", "Standard"], tablefmt="pipe")
      else:
          explorers_output += "None"
  
      # Combine all fields
      return f"""**Chain Details**
  - **Name**: {name}
  - **Chain ID**: {chain_id}
  - **Native Currency**: {currency_info}
  - **TVL**: {tvl}
  {rpc_output}
  
  {explorers_output}
  """

• main.py:83-83 (registration)

  Registration of the tool using FastMCP's @mcp.tool() decorator.

  @mcp.tool()