File size: 9,188 Bytes
1407be5 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 | """MCP (Model Context Protocol) client for remote tool servers.
Supports Streamable HTTP transport (JSON-RPC 2.0 over HTTP).
"""
from __future__ import annotations
import json
import uuid
from typing import Any
import httpx
from .tools import Tool
# ---------------------------------------------------------------------------
# MCP Client
# ---------------------------------------------------------------------------
class MCPClient:
"""Connect to a remote MCP server via Streamable HTTP transport."""
def __init__(
self,
url: str,
headers: dict[str, str] | None = None,
timeout: float = 30.0,
) -> None:
self.url = url
self.headers = headers or {}
self.timeout = timeout
self._session_id: str | None = None
self._initialized = False
# ------------------------------------------------------------------
# Low-level JSON-RPC
# ------------------------------------------------------------------
def _request(self, method: str, params: dict[str, Any] | None = None) -> Any:
"""Send a JSON-RPC request and return the result."""
payload: dict[str, Any] = {
"jsonrpc": "2.0",
"id": str(uuid.uuid4()),
"method": method,
}
if params is not None:
payload["params"] = params
headers = {
"Content-Type": "application/json",
"Accept": "application/json, text/event-stream",
**self.headers,
}
if self._session_id:
headers["Mcp-Session-Id"] = self._session_id
with httpx.Client(timeout=self.timeout) as client:
resp = client.post(self.url, json=payload, headers=headers)
# Capture session ID from response
sid = resp.headers.get("mcp-session-id")
if sid:
self._session_id = sid
resp.raise_for_status()
content_type = resp.headers.get("content-type", "")
# Handle SSE response
if "text/event-stream" in content_type:
return self._parse_sse_response(resp.text)
# Handle JSON response
data = resp.json()
if "error" in data:
raise RuntimeError(f"MCP error: {data['error']}")
return data.get("result")
def _parse_sse_response(self, text: str) -> Any:
"""Parse SSE response text, extracting JSON-RPC results."""
result = None
for line in text.split("\n"):
line = line.strip()
if line.startswith("data:"):
data_str = line[len("data:") :].strip()
if data_str:
try:
data = json.loads(data_str)
if "result" in data:
result = data["result"]
elif "error" in data:
raise RuntimeError(f"MCP error: {data['error']}")
except json.JSONDecodeError:
continue
return result
# ------------------------------------------------------------------
# Lifecycle
# ------------------------------------------------------------------
def initialize(self) -> dict[str, Any]:
"""Initialize the MCP session."""
result = self._request(
"initialize",
{
"protocolVersion": "2025-03-26",
"capabilities": {},
"clientInfo": {"name": "mythos-agent", "version": "0.1.0"},
},
)
self._initialized = True
# Send initialized notification (no response expected)
self._notify("notifications/initialized", {})
return result or {}
def _notify(self, method: str, params: dict[str, Any]) -> None:
"""Send a JSON-RPC notification (no id, no response expected)."""
payload = {"jsonrpc": "2.0", "method": method, "params": params}
headers = {
"Content-Type": "application/json",
"Accept": "application/json, text/event-stream",
**self.headers,
}
if self._session_id:
headers["Mcp-Session-Id"] = self._session_id
with httpx.Client(timeout=self.timeout) as client:
client.post(self.url, json=payload, headers=headers)
# ------------------------------------------------------------------
# Tool discovery
# ------------------------------------------------------------------
def list_tools(self) -> list[dict[str, Any]]:
"""List available tools from the server."""
if not self._initialized:
self.initialize()
result = self._request("tools/list", {})
return (result or {}).get("tools", [])
# ------------------------------------------------------------------
# Tool execution
# ------------------------------------------------------------------
def call_tool(self, name: str, arguments: dict[str, Any]) -> Any:
"""Call a tool on the server."""
if not self._initialized:
self.initialize()
return self._request("tools/call", {"name": name, "arguments": arguments})
# ---------------------------------------------------------------------------
# MCP Tool wrapper
# ---------------------------------------------------------------------------
def _json_schema_type_to_python(type_str: str) -> type:
"""Map JSON Schema type to Python type."""
mapping = {"string": str, "integer": int, "number": float, "boolean": bool, "array": list, "object": dict}
return mapping.get(type_str, str)
def mcp_tool(client: MCPClient, mcp_tool_def: dict[str, Any]) -> Tool:
"""Wrap an MCP tool definition as a local Tool instance.
Args:
client: Connected MCPClient.
mcp_tool_def: Tool dict from ``tools/list`` response.
"""
name = mcp_tool_def["name"]
description = mcp_tool_def.get("description", "")
input_schema = mcp_tool_def.get("inputSchema", {})
# Convert inputSchema to OpenAI-style parameters
properties: dict[str, dict] = {}
for param_name, param_def in input_schema.get("properties", {}).items():
prop: dict[str, Any] = {"type": param_def.get("type", "string")}
if "description" in param_def:
prop["description"] = param_def["description"]
if "enum" in param_def:
prop["enum"] = param_def["enum"]
properties[param_name] = prop
required = input_schema.get("required", [])
parameters = {
"type": "object",
"properties": properties,
"required": required,
}
def handler(**kwargs: Any) -> str:
result = client.call_tool(name, kwargs)
# Extract text content from MCP result
if isinstance(result, dict) and "content" in result:
parts = []
for block in result["content"]:
if isinstance(block, dict) and block.get("type") == "text":
parts.append(block.get("text", ""))
return "\n".join(parts) if parts else json.dumps(result)
return json.dumps(result) if not isinstance(result, str) else result
return Tool(name=name, description=description, parameters=parameters, handler=handler)
# ---------------------------------------------------------------------------
# Convenience: connect and load all tools
# ---------------------------------------------------------------------------
def load_mcp_tools(url: str, headers: dict[str, str] | None = None) -> list[Tool]:
"""Connect to an MCP server and return all its tools as Tool instances."""
client = MCPClient(url=url, headers=headers)
client.initialize()
tools_defs = client.list_tools()
return [mcp_tool(client, td) for td in tools_defs]
# ---------------------------------------------------------------------------
# Pre-configured MCP servers
# ---------------------------------------------------------------------------
MCP_SERVERS: dict[str, dict[str, Any]] = {
"exa": {
"url": "https://mcp.exa.ai/mcp",
"description": "Web search via Exa",
},
"context7": {
"url": "https://mcp.context7.com/mcp",
"description": "Library documentation lookup",
},
"grep_app": {
"url": "https://mcp.grep.app",
"description": "GitHub code search via grep.app",
},
"github": {
"url": "https://gitmcp.io/docs",
"description": "GitHub code search and repository info",
},
}
def load_all_mcp_tools(
servers: dict[str, dict[str, Any]] | None = None,
) -> dict[str, list[Tool]]:
"""Load tools from all configured MCP servers.
Returns:
``{server_name: [Tool, ...]}``
"""
if servers is None:
servers = MCP_SERVERS
result: dict[str, list[Tool]] = {}
for name, cfg in servers.items():
try:
result[name] = load_mcp_tools(
url=cfg["url"],
headers=cfg.get("headers"),
)
except Exception as e:
print(f"[MCP] Failed to load {name}: {e}")
result[name] = []
return result
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