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Make mcp-agent Context a derivative of FastMCP context #504

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Merged
merged 13 commits into from
Oct 21, 2025
Merged

Make mcp-agent Context a derivative of FastMCP context #504

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efbfbd6
Make mcp-agent Context a derivative of FastMCP context
saqadri Sep 17, 2025
e203904
Merge branch 'main' into feat/app_context_is_mcp_context
saqadri Sep 17, 2025
8d6457a
Merge branch 'main' into feat/app_context_is_mcp_context
saqadri Sep 17, 2025
f30337a
Lint and format
saqadri Sep 17, 2025
53ec2e7
Merge branch 'main' into feat/app_context_is_mcp_context
saqadri Oct 9, 2025
458b76f
checkpoint
saqadri Oct 10, 2025
9999b17
Fixed and updates
saqadri Oct 10, 2025
c55e9df
Update mcp dependency to 1.18.0, and support additional tool decorato…
saqadri Oct 20, 2025
83b348e
fix failing tests
saqadri Oct 21, 2025
7b9d0af
Various fixes
saqadri Oct 21, 2025
1bd4b41
PR feedback
saqadri Oct 21, 2025
d8bbab1
Merge branch 'main' into feat/app_context_is_mcp_context
saqadri Oct 21, 2025
08839a5
Fix tests
saqadri Oct 21, 2025
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2 changes: 1 addition & 1 deletion pyproject.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ dependencies = [
"fastapi>=0.115.6",
"httpx>=0.28.1",
"jsonref>=1.1.0",
"mcp>=1.13.1",
"mcp>=1.18.0",
"numpy>=2.1.3",
"opentelemetry-distro>=0.50b0",
"opentelemetry-exporter-otlp-proto-http>=1.29.0",
Expand Down
143 changes: 130 additions & 13 deletions src/mcp_agent/app.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2,11 +2,12 @@
import os
import sys
import functools

from types import MethodType
from typing import (
Any,
Dict,
Iterable,
Mapping,
Optional,
Type,
TypeVar,
Expand All @@ -20,6 +21,8 @@

from mcp import ServerSession
from mcp.server.fastmcp import FastMCP
from mcp.types import ToolAnnotations, Icon

from mcp_agent.core.context import Context, initialize_context, cleanup_context
from mcp_agent.config import Settings, get_settings
from mcp_agent.executor.signal_registry import SignalRegistry
Expand Down Expand Up @@ -586,6 +589,7 @@ def _create_workflow_from_function(
async def _invoke_target(workflow_self, *args, **kwargs):
# Inject app_ctx (AppContext) and shim ctx (FastMCP Context) if requested by the function
import inspect as _inspect
import typing as _typing

call_kwargs = dict(kwargs)

Expand Down Expand Up @@ -622,24 +626,51 @@ async def _invoke_target(workflow_self, *args, **kwargs):
except Exception:
pass

# If the function expects a FastMCP Context (ctx/context), ensure it's present (None inside workflow)
# If the function expects a FastMCP Context (ctx/context), ensure it's present.
try:
from mcp.server.fastmcp import Context as _Ctx # type: ignore
except Exception:
_Ctx = None # type: ignore

def _is_fast_ctx_annotation(annotation) -> bool:
if _Ctx is None or annotation is _inspect._empty:
return False
if annotation is _Ctx:
return True
try:
origin = _typing.get_origin(annotation)
if origin is not None:
return any(
_is_fast_ctx_annotation(arg)
for arg in _typing.get_args(annotation)
)
except Exception:
pass
try:
return "fastmcp" in str(annotation)
except Exception:
return False

try:
sig = sig if "sig" in locals() else _inspect.signature(fn)
for p in sig.parameters.values():
if (
p.annotation is not _inspect._empty
and _Ctx is not None
and p.annotation is _Ctx
needs_fast_ctx = False
if _is_fast_ctx_annotation(p.annotation):
needs_fast_ctx = True
elif p.annotation is _inspect._empty and p.name in (
"ctx",
"context",
):
if p.name not in call_kwargs:
call_kwargs[p.name] = None
if p.name in ("ctx", "context") and p.name not in call_kwargs:
call_kwargs[p.name] = None
needs_fast_ctx = True
if needs_fast_ctx and p.name not in call_kwargs:
fast_ctx = getattr(workflow_self, "_mcp_request_context", None)
if fast_ctx is None and app_context_param_name:
fast_ctx = getattr(
call_kwargs.get(app_context_param_name, None),
"fastmcp",
None,
)
call_kwargs[p.name] = fast_ctx
except Exception:
pass

Expand Down Expand Up @@ -739,15 +770,23 @@ def tool(
self,
name: str | None = None,
*,
title: str | None = None,
description: str | None = None,
annotations: ToolAnnotations | Mapping[str, Any] | None = None,
icons: Iterable[Icon | Mapping[str, Any]] | None = None,
meta: Mapping[str, Any] | None = None,
structured_output: bool | None = None,
) -> Callable[[Callable[P, R]], Callable[P, R]]: ...

def tool(
self,
name: str | None = None,
*,
title: str | None = None,
description: str | None = None,
annotations: ToolAnnotations | Mapping[str, Any] | None = None,
icons: Iterable[Icon | Mapping[str, Any]] | None = None,
meta: Mapping[str, Any] | None = None,
structured_output: bool | None = None,
):
"""
Expand All @@ -766,6 +805,28 @@ def decorator(fn: Callable[P, R]) -> Callable[P, R]:

validate_tool_schema(fn, tool_name)

annotations_obj: ToolAnnotations | None = None
if annotations is not None:
if isinstance(annotations, ToolAnnotations):
annotations_obj = annotations
else:
annotations_obj = ToolAnnotations(**dict(annotations))

icons_list: list[Icon] | None = None
if icons is not None:
icons_list = []
for icon in icons:
if isinstance(icon, Icon):
icons_list.append(icon)
elif isinstance(icon, Mapping):
icons_list.append(Icon(**icon))
else:
raise TypeError("icons entries must be Icon or mapping")

meta_payload: Dict[str, Any] | None = None
if meta is not None:
meta_payload = dict(meta)

# Construct the workflow from function
workflow_cls = self._create_workflow_from_function(
fn,
Expand All @@ -784,13 +845,25 @@ def decorator(fn: Callable[P, R]) -> Callable[P, R]:
"source_fn": fn,
"structured_output": structured_output,
"description": description or (fn.__doc__ or ""),
"title": title,
"annotations": annotations_obj,
"icons": icons_list,
"meta": meta_payload,
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Should this be _meta?

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Hmmm I looked at the MCP SDK and it looks like the decorator has meta, not _meta. Where did you see _meta?

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Ah, _meta is what's used by openai apps -- https://developers.openai.com/apps-sdk/build/mcp-server

Looking at the MCP docs it seems it may be abused for that reason -- https://github.com/modelcontextprotocol/modelcontextprotocol/blob/47339c03c143bb4ec01a26e721a1b8fe66634ebe/docs/specification/draft/basic/index.mdx#_meta -- since supposed to be reserved for MCP itself

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So meta on the tool decorator will be set as _meta on the actual tool registration in MCP. See modelcontextprotocol/python-sdk#1463

However that change needs to land in pypi first so we can consume it

}
)

return fn

# Support bare usage: @app.tool without parentheses
if callable(name) and description is None and structured_output is None:
if (
callable(name)
and title is None
and description is None
and annotations is None
and icons is None
and meta is None
and structured_output is None
):
_fn = name # type: ignore[assignment]
name = None
return decorator(_fn) # type: ignore[arg-type]
Expand All @@ -805,14 +878,24 @@ def async_tool(
self,
name: str | None = None,
*,
title: str | None = None,
description: str | None = None,
annotations: ToolAnnotations | Mapping[str, Any] | None = None,
icons: Iterable[Icon | Mapping[str, Any]] | None = None,
meta: Mapping[str, Any] | None = None,
structured_output: bool | None = None,
) -> Callable[[Callable[P, R]], Callable[P, R]]: ...

def async_tool(
self,
name: str | None = None,
*,
title: str | None = None,
description: str | None = None,
annotations: ToolAnnotations | Mapping[str, Any] | None = None,
icons: Iterable[Icon | Mapping[str, Any]] | None = None,
meta: Mapping[str, Any] | None = None,
structured_output: bool | None = None,
):
"""
Decorator to declare an asynchronous MCP tool.
Expand All @@ -830,6 +913,28 @@ def decorator(fn: Callable[P, R]) -> Callable[P, R]:

validate_tool_schema(fn, workflow_name)

annotations_obj: ToolAnnotations | None = None
if annotations is not None:
if isinstance(annotations, ToolAnnotations):
annotations_obj = annotations
else:
annotations_obj = ToolAnnotations(**dict(annotations))

icons_list: list[Icon] | None = None
if icons is not None:
icons_list = []
for icon in icons:
if isinstance(icon, Icon):
icons_list.append(icon)
elif isinstance(icon, Mapping):
icons_list.append(Icon(**icon))
else:
raise TypeError("icons entries must be Icon or mapping")

meta_payload: Dict[str, Any] | None = None
if meta is not None:
meta_payload = dict(meta)

workflow_cls = self._create_workflow_from_function(
fn,
workflow_name=workflow_name,
Expand All @@ -844,14 +949,26 @@ def decorator(fn: Callable[P, R]) -> Callable[P, R]:
"workflow_name": workflow_name,
"workflow_cls": workflow_cls,
"source_fn": fn,
"structured_output": None,
"structured_output": structured_output,
"description": description or (fn.__doc__ or ""),
"title": title,
"annotations": annotations_obj,
"icons": icons_list,
"meta": meta_payload,
}
)
return fn

# Support bare usage: @app.async_tool without parentheses
if callable(name) and description is None:
if (
callable(name)
and title is None
and description is None
and annotations is None
and icons is None
and meta is None
and structured_output is None
):
_fn = name # type: ignore[assignment]
name = None
return decorator(_fn) # type: ignore[arg-type]
Expand Down
10 changes: 3 additions & 7 deletions src/mcp_agent/cli/cloud/commands/deploy/main.py
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Original file line number Diff line number Diff line change
Expand Up @@ -173,9 +173,7 @@ def deploy_config(

if app_name is None:
if default_app_name:
print_info(
f"Using app name from config.yaml: '{default_app_name}'"
)
print_info(f"Using app name from config.yaml: '{default_app_name}'")
app_name = default_app_name
else:
app_name = "default"
Expand Down Expand Up @@ -205,7 +203,7 @@ def deploy_config(
" • Or use the --api-key flag with your key",
retriable=False,
)

if settings.VERBOSE:
print_info(f"Using API at {effective_api_url}")

Expand All @@ -231,9 +229,7 @@ def deploy_config(
print_info(f"New app id: `{app_id}`")
else:
short_id = f"{app_id[:8]}…"
print_success(
f"Found existing app '{app_name}' (ID: `{short_id}`)"
)
print_success(f"Found existing app '{app_name}' (ID: `{short_id}`)")
if not non_interactive:
use_existing = typer.confirm(
f"Deploy an update to '{app_name}' (ID: `{short_id}`)?",
Expand Down
4 changes: 3 additions & 1 deletion src/mcp_agent/cli/cloud/commands/deploy/wrangler_wrapper.py
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Original file line number Diff line number Diff line change
Expand Up @@ -296,7 +296,9 @@ def ignore_patterns(path_str, names):
)
meta_vars.update({"MCP_DEPLOY_WORKSPACE_HASH": bundle_hash})
if settings.VERBOSE:
print_info(f"Deploying from non-git workspace (hash {bundle_hash[:12]}…)")
print_info(
f"Deploying from non-git workspace (hash {bundle_hash[:12]}…)"
)

# Write a breadcrumb file into the project so it ships with the bundle.
# Use a Python file for guaranteed inclusion without renaming.
Expand Down
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