a digital entity named phi that roams bsky
phi.zzstoatzz.io
fix MCP cancel scope error by creating fresh servers per run
shared MCPServerStreamableHTTP instances get entered/exited across
different async tasks when concurrent notifications arrive, triggering
"Attempted to exit cancel scope in a different task than it was entered in".
fix: create fresh MCP server instances per agent.run() call via the
toolsets parameter instead of sharing singletons on the agent.
ref: https://github.com/pydantic/pydantic-ai/issues/2818
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
+22
-20
+22
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src/bot/agent.py
+22
-20
src/bot/agent.py
···
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self.memory = None
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logger.warning("no memory - missing turbopuffer or openai key")
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# Generic atproto record CRUD via hosted pdsx MCP
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pdsx_mcp = MCPServerStreamableHTTP(
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url="https://pdsx-by-zzstoatzz.fastmcp.app/mcp",
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timeout=30,
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headers={
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"x-atproto-handle": settings.bluesky_handle,
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"x-atproto-password": settings.bluesky_password,
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},
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)
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-
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# ATProto publication search via hosted pub-search MCP
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pub_search_mcp = MCPServerStreamableHTTP(
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url="https://pub-search-by-zzstoatzz.fastmcp.app/mcp",
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timeout=30,
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tool_prefix="pub",
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-
)
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-
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# Create PydanticAI agent with MCP tools
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+
# Create PydanticAI agent without MCP toolsets — they're created
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# fresh per agent.run() call to avoid the cancel scope bug:
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# https://github.com/pydantic/pydantic-ai/issues/2818
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self.agent = Agent[PhiDeps, Response](
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name="phi",
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model="anthropic:claude-sonnet-4-6",
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system_prompt=f"{self.base_personality}\n\n{OPERATIONAL_INSTRUCTIONS}",
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output_type=Response,
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deps_type=PhiDeps,
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toolsets=[pdsx_mcp, pub_search_mcp],
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)
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# --- memory tools ---
···
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logger.info("phi agent initialized with pdsx + pub-search mcp tools")
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+
def _mcp_toolsets(self) -> list[MCPServerStreamableHTTP]:
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+
"""Create fresh MCP server instances for a single agent run."""
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+
return [
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+
MCPServerStreamableHTTP(
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url="https://pdsx-by-zzstoatzz.fastmcp.app/mcp",
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+
timeout=30,
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+
headers={
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"x-atproto-handle": settings.bluesky_handle,
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"x-atproto-password": settings.bluesky_password,
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+
},
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+
),
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+
MCPServerStreamableHTTP(
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url="https://pub-search-by-zzstoatzz.fastmcp.app/mcp",
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+
timeout=30,
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tool_prefix="pub",
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),
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+
]
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+
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async def process_mention(
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self,
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mention_text: str,
···
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memory=self.memory,
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thread_uri=thread_uri,
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)
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result = await self.agent.run(user_prompt, deps=deps)
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+
result = await self.agent.run(user_prompt, deps=deps, toolsets=self._mcp_toolsets())
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logger.info(f"agent decided: {result.output.action}" + (f" - {result.output.text[:80]}" if result.output.text else "") + (f" ({result.output.reason})" if result.output.reason else ""))
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# Store interaction and extract observations