fix(adapters): wrap redacted MCP output in CallToolResult

When mcp_check_output returns redacted_data, the interceptor was
returning a plain str. langchain-mcp-adapters expects MCPToolCallResult
(CallToolResult | ToolMessage | Command) and calls .content on the
return value, causing AttributeError at runtime.

Now wraps the redacted string in a CallToolResult with a single
TextContent block, which is the correct return type for the interceptor
protocol. Also adds mcp>=1.0.0 as a new 'langgraph' optional extra and
to dev dependencies, with a lazy import that surfaces a clear error
message if mcp is not installed.

Fixes #119

Author: gzak

axonflow/adapters/langgraph.py

@@ -34,8 +34,11 @@
 
 import asyncio
 import json
+from collections.abc import Callable
 from dataclasses import dataclass, field
-from typing import TYPE_CHECKING, Any, Callable
+from typing import TYPE_CHECKING, Any
+
+from mcp.types import CallToolResult, TextContent
 
 from axonflow.exceptions import PolicyViolationError
 from axonflow.workflow import (
@@ -573,7 +576,9 @@ async def _interceptor(request: Any, handler: Callable[..., Any]) -> Any:
                     output_check.block_reason or "Tool result blocked by policy"
                 )
             if output_check.redacted_data is not None:
-                return output_check.redacted_data
+                return CallToolResult(
+                    content=[TextContent(type="text", text=output_check.redacted_data)]
+                )
 
             return result
 

axonflow/interceptors/anthropic.py

@@ -25,8 +25,9 @@
 from __future__ import annotations
 
 import asyncio
+from collections.abc import Callable
 from functools import wraps
-from typing import TYPE_CHECKING, Any, Callable, TypeVar
+from typing import TYPE_CHECKING, Any, TypeVar
 
 from axonflow.exceptions import PolicyViolationError
 from axonflow.interceptors.base import BaseInterceptor

axonflow/interceptors/bedrock.py

@@ -28,8 +28,9 @@
 
 import asyncio
 import json
+from collections.abc import Callable
 from functools import wraps
-from typing import TYPE_CHECKING, Any, Callable, TypeVar
+from typing import TYPE_CHECKING, Any, TypeVar
 
 from axonflow.exceptions import PolicyViolationError
 from axonflow.interceptors.base import BaseInterceptor

axonflow/interceptors/gemini.py

@@ -22,8 +22,9 @@
 from __future__ import annotations
 
 import asyncio
+from collections.abc import Callable
 from functools import wraps
-from typing import TYPE_CHECKING, Any, Callable, TypeVar
+from typing import TYPE_CHECKING, Any, TypeVar
 
 from axonflow.exceptions import PolicyViolationError
 from axonflow.interceptors.base import BaseInterceptor

axonflow/interceptors/ollama.py

@@ -27,8 +27,9 @@
 from __future__ import annotations
 
 import asyncio
+from collections.abc import Callable
 from functools import wraps
-from typing import TYPE_CHECKING, Any, Callable, TypeVar
+from typing import TYPE_CHECKING, Any, TypeVar
 
 from axonflow.exceptions import PolicyViolationError
 from axonflow.interceptors.base import BaseInterceptor

axonflow/interceptors/openai.py

@@ -24,8 +24,9 @@
 from __future__ import annotations
 
 import asyncio
+from collections.abc import Callable
 from functools import wraps
-from typing import TYPE_CHECKING, Any, Callable, TypeVar
+from typing import TYPE_CHECKING, Any, TypeVar
 
 from axonflow.exceptions import PolicyViolationError
 from axonflow.interceptors.base import BaseInterceptor

axonflow/masfeat.py

@@ -11,7 +11,7 @@
 from dataclasses import dataclass, field
 from datetime import datetime
 from enum import Enum
-from typing import Any, Optional
+from typing import Any
 
 # Python's datetime.fromisoformat requires exactly 6 fractional digits
 _MICROSECOND_PRECISION = 6
@@ -121,8 +121,8 @@ class Finding:
     category: str
     description: str
     status: FindingStatus
-    remediation: Optional[str] = None
-    due_date: Optional[datetime] = None
+    remediation: str | None = None
+    due_date: datetime | None = None
 
 
 # ===========================================================================
@@ -140,18 +140,18 @@ class AISystemRegistry:
     system_name: str
     use_case: AISystemUseCase
     owner_team: str
-    customer_impact: Optional[int]
-    model_complexity: Optional[int]
-    human_reliance: Optional[int]
+    customer_impact: int | None
+    model_complexity: int | None
+    human_reliance: int | None
     materiality: MaterialityClassification
     status: SystemStatus
-    created_at: Optional[datetime]
-    updated_at: Optional[datetime]
-    description: Optional[str] = None
-    technical_owner: Optional[str] = None
-    business_owner: Optional[str] = None
-    metadata: Optional[dict[str, Any]] = None
-    created_by: Optional[str] = None
+    created_at: datetime | None
+    updated_at: datetime | None
+    description: str | None = None
+    technical_owner: str | None = None
+    business_owner: str | None = None
+    metadata: dict[str, Any] | None = None
+    created_by: str | None = None
 
 
 @dataclass
@@ -181,25 +181,25 @@ class FEATAssessment:
     system_id: str
     assessment_type: str
     status: FEATAssessmentStatus
-    assessment_date: Optional[datetime]
-    created_at: Optional[datetime]
-    updated_at: Optional[datetime]
-    valid_until: Optional[datetime] = None
-    fairness_score: Optional[int] = None
-    ethics_score: Optional[int] = None
-    accountability_score: Optional[int] = None
-    transparency_score: Optional[int] = None
-    overall_score: Optional[int] = None
-    fairness_details: Optional[dict[str, Any]] = None
-    ethics_details: Optional[dict[str, Any]] = None
-    accountability_details: Optional[dict[str, Any]] = None
-    transparency_details: Optional[dict[str, Any]] = None
-    findings: Optional[list[Finding]] = None
-    recommendations: Optional[list[str]] = None
-    assessors: Optional[list[str]] = None
-    approved_by: Optional[str] = None
-    approved_at: Optional[datetime] = None
-    created_by: Optional[str] = None
+    assessment_date: datetime | None
+    created_at: datetime | None
+    updated_at: datetime | None
+    valid_until: datetime | None = None
+    fairness_score: int | None = None
+    ethics_score: int | None = None
+    accountability_score: int | None = None
+    transparency_score: int | None = None
+    overall_score: int | None = None
+    fairness_details: dict[str, Any] | None = None
+    ethics_details: dict[str, Any] | None = None
+    accountability_details: dict[str, Any] | None = None
+    transparency_details: dict[str, Any] | None = None
+    findings: list[Finding] | None = None
+    recommendations: list[str] | None = None
+    assessors: list[str] | None = None
+    approved_by: str | None = None
+    approved_at: datetime | None = None
+    created_by: str | None = None
 
 
 # ===========================================================================
@@ -216,16 +216,16 @@ class KillSwitch:
     system_id: str
     status: KillSwitchStatus
     auto_trigger_enabled: bool
-    created_at: Optional[datetime]
-    updated_at: Optional[datetime]
-    accuracy_threshold: Optional[float] = None
-    bias_threshold: Optional[float] = None
-    error_rate_threshold: Optional[float] = None
-    triggered_at: Optional[datetime] = None
-    triggered_by: Optional[str] = None
-    triggered_reason: Optional[str] = None
-    restored_at: Optional[datetime] = None
-    restored_by: Optional[str] = None
+    created_at: datetime | None
+    updated_at: datetime | None
+    accuracy_threshold: float | None = None
+    bias_threshold: float | None = None
+    error_rate_threshold: float | None = None
+    triggered_at: datetime | None = None
+    triggered_by: str | None = None
+    triggered_reason: str | None = None
+    restored_at: datetime | None = None
+    restored_by: str | None = None
 
 
 @dataclass
@@ -235,17 +235,17 @@ class KillSwitchEvent:
     id: str
     kill_switch_id: str
     event_type: KillSwitchEventType
-    created_at: Optional[datetime]
-    event_data: Optional[dict[str, Any]] = None
-    created_by: Optional[str] = None
+    created_at: datetime | None
+    event_data: dict[str, Any] | None = None
+    created_by: str | None = None
 
 
 # ===========================================================================
 # Helper Functions
 # ===========================================================================
 
 
-def _parse_datetime(value: Any) -> Optional[datetime]:
+def _parse_datetime(value: Any) -> datetime | None:
     """Parse datetime from API response."""
     if value is None:
         return None
@@ -358,7 +358,7 @@ def finding_to_dict(finding: Finding) -> dict[str, Any]:
     return result
 
 
-def _parse_findings(data: Optional[list[dict[str, Any]]]) -> Optional[list[Finding]]:
+def _parse_findings(data: list[dict[str, Any]] | None) -> list[Finding] | None:
     """Parse list of findings from API response."""
     if data is None:
         return None

axonflow/utils/retry.py

@@ -2,7 +2,8 @@
 
 from __future__ import annotations
 
-from typing import Any, Callable, TypeVar
+from collections.abc import Callable
+from typing import Any, TypeVar
 
 from tenacity import (
     RetryCallState,

pyproject.toml

@@ -24,22 +24,20 @@ classifiers = [
     "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
     "Topic :: Software Development :: Libraries :: Python Modules",
     "Topic :: Scientific/Engineering :: Artificial Intelligence",
     "Typing :: Typed",
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 dependencies = [
     "httpx>=0.25.0",
     "pydantic>=2.0.0",
     "tenacity>=8.0.0",
     "structlog>=23.0.0",
     "cachetools>=5.0.0",
-    "eval_type_backport>=0.2.0; python_version < '3.10'",
 ]
 
 [project.optional-dependencies]
@@ -54,6 +52,7 @@ dev = [
     "black>=23.0.0",
     "isort>=5.12.0",
     "pre-commit>=3.0.0",
+    "mcp>=1.0.0",
 ]
 docs = [
     "sphinx>=7.0.0",
@@ -63,9 +62,11 @@ docs = [
 ]
 openai = ["openai>=1.0.0"]
 anthropic = ["anthropic>=0.18.0"]
+langgraph = ["mcp>=1.0.0"]
 all = [
     "openai>=1.0.0",
     "anthropic>=0.18.0",
+    "mcp>=1.0.0",
 ]
 
 [project.urls]
@@ -83,7 +84,7 @@ include = ["axonflow*"]
 axonflow = ["py.typed"]
 
 [tool.ruff]
-target-version = "py39"
+target-version = "py310"
 line-length = 100
 
 [tool.ruff.lint]
@@ -148,7 +149,7 @@ ignore = [
 known-first-party = ["axonflow"]
 
 [tool.mypy]
-python_version = "3.9"
+python_version = "3.10"
 strict = true
 warn_return_any = true
 warn_unused_configs = true
@@ -169,6 +170,7 @@ show_column_numbers = true
 module = "tests.*"
 disallow_untyped_defs = false
 
+
 [tool.pytest.ini_options]
 asyncio_mode = "auto"
 testpaths = ["tests"]

tests/test_langgraph_adapter.py

@@ -7,6 +7,7 @@
 from unittest.mock import AsyncMock, MagicMock
 
 import pytest
+from mcp.types import CallToolResult, TextContent
 
 from axonflow import AxonFlow
 from axonflow.adapters.langgraph import AxonFlowLangGraphAdapter, MCPInterceptorOptions
@@ -192,7 +193,10 @@ async def test_returns_redacted_data_when_present(
 
         result = await adapter.mcp_tool_interceptor()(MagicMock(), handler)
 
-        assert result == "[REDACTED]"
+        assert isinstance(result, CallToolResult)
+        assert len(result.content) == 1
+        assert isinstance(result.content[0], TextContent)
+        assert result.content[0].text == "[REDACTED]"
 
     @pytest.mark.asyncio
     async def test_returns_original_result_when_no_redaction(