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282 | class MCPManager:
"""Manages MCP server connections and distributes resource providers."""
def __init__(
self,
name: str = "mcp",
owner: str | None = None,
servers: Sequence[MCPServerConfig | str] | None = None,
context: NodeContext | None = None,
progress_handler: RichProgressCallback | None = None,
accessible_roots: list[str] | None = None,
):
self.name = name
self.owner = owner
self.servers: list[MCPServerConfig] = []
for server in servers or []:
self.add_server_config(server)
self.context = context
self.providers: list[MCPResourceProvider] = []
self.aggregating_provider = AggregatingResourceProvider(
providers=cast(list[ResourceProvider], self.providers),
name=f"{name}_aggregated",
)
self.exit_stack = AsyncExitStack()
self._progress_handler = progress_handler
self._accessible_roots = accessible_roots
def add_server_config(self, cfg: MCPServerConfig | str):
"""Add a new MCP server to the manager."""
resolved = BaseMCPServerConfig.from_string(cfg) if isinstance(cfg, str) else cfg
self.servers.append(resolved)
def __repr__(self) -> str:
return f"MCPManager(name={self.name!r}, servers={len(self.servers)})"
async def __aenter__(self) -> Self:
try:
# Setup directly provided servers and context servers concurrently
tasks = [self._setup_server(server) for server in self.servers]
if self.context and self.context.config and self.context.config.mcp_servers:
tasks.extend(
self._setup_server(server)
for server in self.context.config.get_mcp_servers()
)
if tasks:
await asyncio.gather(*tasks)
except Exception as e:
# Clean up in case of error
await self.__aexit__(type(e), e, e.__traceback__)
msg = "Failed to initialize MCP manager"
raise RuntimeError(msg) from e
return self
async def __aexit__(
self,
exc_type: type[BaseException] | None,
exc_val: BaseException | None,
exc_tb: TracebackType | None,
):
await self.cleanup()
async def _elicitation_callback(
self,
message: str,
response_type: type[Any],
params: types.ElicitRequestParams,
context: RequestContext,
) -> ElicitResult[dict[str, Any]] | dict[str, Any] | None:
"""Handle elicitation requests from MCP server."""
from fastmcp.client.elicitation import ElicitResult
from mcp import types
from llmling_agent.agent.context import AgentContext
if self.context and isinstance(self.context, AgentContext):
legacy_result = await self.context.handle_elicitation(params)
# Convert legacy MCP result to FastMCP format
if isinstance(legacy_result, types.ElicitResult):
if legacy_result.action == "accept" and legacy_result.content:
return legacy_result.content
return ElicitResult(action=legacy_result.action)
if isinstance(legacy_result, types.ErrorData):
return ElicitResult(action="cancel")
return ElicitResult(action="decline")
return ElicitResult(action="decline")
async def _sampling_callback(
self,
messages: list[SamplingMessage],
params: types.CreateMessageRequestParams,
context: RequestContext,
) -> str:
"""Handle MCP sampling by creating a new agent with specified preferences."""
from mcp import types
from llmling_agent.agent import Agent
try:
# Convert messages to prompts for the agent
prompts: list[BaseContent | str] = []
for mcp_msg in messages:
match mcp_msg.content:
case types.TextContent(text=text):
prompts.append(text)
case types.ImageContent(data=data, mimeType=mime_type):
our_image = ImageBase64Content(data=data, mime_type=mime_type)
prompts.append(our_image)
case types.AudioContent(data=data, mimeType=mime_type):
fmt = mime_type.removeprefix("audio/")
our_audio = AudioBase64Content(data=data, format=fmt)
prompts.append(our_audio)
# Extract model from preferences
model = None
if (
params.modelPreferences
and params.modelPreferences.hints
and params.modelPreferences.hints[0].name
):
model = params.modelPreferences.hints[0].name
# Create usage limits from sampling parameters
usage_limits = UsageLimits(
output_tokens_limit=params.maxTokens,
request_limit=1, # Single sampling request
)
# TODO: Apply temperature from params.temperature
# Currently no direct way to pass temperature to Agent constructor
# May need provider-level configuration or runtime model settings
# Create agent with sampling parameters
agent = Agent(
name="mcp-sampling-agent",
model=model,
system_prompt=params.systemPrompt or "",
session=False, # Don't store history for sampling
)
async with agent:
# Pass all prompts directly to the agent
result = await agent.run(
*prompts,
store_history=False,
usage_limits=usage_limits,
)
return str(result.content)
except Exception as e:
logger.exception("Sampling failed")
return f"Sampling failed: {e!s}"
async def _setup_server(self, config: MCPServerConfig) -> None:
"""Set up a single MCP server resource provider."""
if not config.enabled:
return
provider = MCPResourceProvider(
server=config,
name=f"{self.name}_{config.client_id}",
owner=self.owner,
context=self.context,
source="pool" if self.owner == "pool" else "node",
elicitation_callback=self._elicitation_callback,
sampling_callback=self._sampling_callback,
progress_handler=self._progress_handler,
accessible_roots=self._accessible_roots,
)
# Initialize the provider and add to exit stack
provider = await self.exit_stack.enter_async_context(provider)
self.providers.append(provider)
def get_mcp_providers(self) -> list[MCPResourceProvider]:
"""Get all MCP resource providers managed by this manager."""
return list(self.providers)
def get_aggregating_provider(self) -> AggregatingResourceProvider:
"""Get the aggregating provider that contains all MCP providers."""
return self.aggregating_provider
async def setup_server_runtime(self, config: MCPServerConfig) -> MCPResourceProvider:
"""Set up a single MCP server at runtime while manager is running.
Returns:
The newly created and initialized MCPResourceProvider
"""
if not config.enabled:
msg = f"Server config {config.client_id} is disabled"
raise ValueError(msg)
# Add the config first
self.add_server_config(config)
# Create and initialize the provider
provider = MCPResourceProvider(
server=config,
name=f"{self.name}_{config.client_id}",
owner=self.owner,
context=self.context,
source="pool" if self.owner == "pool" else "node",
elicitation_callback=self._elicitation_callback,
sampling_callback=self._sampling_callback,
progress_handler=self._progress_handler,
accessible_roots=self._accessible_roots,
)
# Initialize the provider and add to exit stack
provider = await self.exit_stack.enter_async_context(provider)
self.providers.append(provider)
# Note: AggregatingResourceProvider automatically sees the new provider
# since it references self.providers list
return provider
async def cleanup(self) -> None:
"""Clean up all MCP connections and providers."""
try:
try:
# Clean up exit stack (which includes MCP providers)
await self.exit_stack.aclose()
except RuntimeError as e:
if "different task" in str(e):
# Handle task context mismatch
current_task = asyncio.current_task()
if current_task:
loop = asyncio.get_running_loop()
await loop.create_task(self.exit_stack.aclose())
else:
raise
self.providers.clear()
except Exception as e:
msg = "Error during MCP manager cleanup"
logger.exception(msg, exc_info=e)
raise RuntimeError(msg) from e
@property
def active_servers(self) -> list[str]:
"""Get IDs of active servers."""
return [provider.server.client_id for provider in self.providers]
|