feat: extract mcp tool usage (#31802)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
This commit is contained in:
wangxiaolei
2026-02-09 09:52:14 +08:00
committed by GitHub
parent aa800d838d
commit 483db22b97
2 changed files with 332 additions and 2 deletions

View File

@@ -3,8 +3,8 @@ from __future__ import annotations
import base64
import json
import logging
from collections.abc import Generator
from typing import Any
from collections.abc import Generator, Mapping
from typing import Any, cast
from core.mcp.auth_client import MCPClientWithAuthRetry
from core.mcp.error import MCPConnectionError
@@ -17,6 +17,7 @@ from core.mcp.types import (
TextContent,
TextResourceContents,
)
from core.model_runtime.entities.llm_entities import LLMUsage, LLMUsageMetadata
from core.tools.__base.tool import Tool
from core.tools.__base.tool_runtime import ToolRuntime
from core.tools.entities.tool_entities import ToolEntity, ToolInvokeMessage, ToolProviderType
@@ -46,6 +47,7 @@ class MCPTool(Tool):
self.headers = headers or {}
self.timeout = timeout
self.sse_read_timeout = sse_read_timeout
self._latest_usage = LLMUsage.empty_usage()
def tool_provider_type(self) -> ToolProviderType:
return ToolProviderType.MCP
@@ -59,6 +61,10 @@ class MCPTool(Tool):
message_id: str | None = None,
) -> Generator[ToolInvokeMessage, None, None]:
result = self.invoke_remote_mcp_tool(tool_parameters)
# Extract usage metadata from MCP protocol's _meta field
self._latest_usage = self._derive_usage_from_result(result)
# handle dify tool output
for content in result.content:
if isinstance(content, TextContent):
@@ -120,6 +126,99 @@ class MCPTool(Tool):
for item in json_list:
yield self.create_json_message(item)
@property
def latest_usage(self) -> LLMUsage:
return self._latest_usage
@classmethod
def _derive_usage_from_result(cls, result: CallToolResult) -> LLMUsage:
"""
Extract usage metadata from MCP tool result's _meta field.
The MCP protocol's _meta field (aliased as 'meta' in Python) can contain
usage information such as token counts, costs, and other metadata.
Args:
result: The CallToolResult from MCP tool invocation
Returns:
LLMUsage instance with values from meta or empty_usage if not found
"""
# Extract usage from the meta field if present
if result.meta:
usage_dict = cls._extract_usage_dict(result.meta)
if usage_dict is not None:
return LLMUsage.from_metadata(cast(LLMUsageMetadata, cast(object, dict(usage_dict))))
return LLMUsage.empty_usage()
@classmethod
def _extract_usage_dict(cls, payload: Mapping[str, Any]) -> Mapping[str, Any] | None:
"""
Recursively search for usage dictionary in the payload.
The MCP protocol's _meta field can contain usage data in various formats:
- Direct usage field: {"usage": {...}}
- Nested in metadata: {"metadata": {"usage": {...}}}
- Or nested within other fields
Args:
payload: The payload to search for usage data
Returns:
The usage dictionary if found, None otherwise
"""
# Check for direct usage field
usage_candidate = payload.get("usage")
if isinstance(usage_candidate, Mapping):
return usage_candidate
# Check for metadata nested usage
metadata_candidate = payload.get("metadata")
if isinstance(metadata_candidate, Mapping):
usage_candidate = metadata_candidate.get("usage")
if isinstance(usage_candidate, Mapping):
return usage_candidate
# Check for common token counting fields directly in payload
# Some MCP servers may include token counts directly
if "total_tokens" in payload or "prompt_tokens" in payload or "completion_tokens" in payload:
usage_dict: dict[str, Any] = {}
for key in (
"prompt_tokens",
"completion_tokens",
"total_tokens",
"prompt_unit_price",
"completion_unit_price",
"total_price",
"currency",
"prompt_price_unit",
"completion_price_unit",
"prompt_price",
"completion_price",
"latency",
"time_to_first_token",
"time_to_generate",
):
if key in payload:
usage_dict[key] = payload[key]
if usage_dict:
return usage_dict
# Recursively search through nested structures
for value in payload.values():
if isinstance(value, Mapping):
found = cls._extract_usage_dict(value)
if found is not None:
return found
elif isinstance(value, list) and not isinstance(value, (str, bytes, bytearray)):
for item in value:
if isinstance(item, Mapping):
found = cls._extract_usage_dict(item)
if found is not None:
return found
return None
def fork_tool_runtime(self, runtime: ToolRuntime) -> MCPTool:
return MCPTool(
entity=self.entity,

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@@ -1,4 +1,5 @@
import base64
from decimal import Decimal
from unittest.mock import Mock, patch
import pytest
@@ -9,8 +10,10 @@ from core.mcp.types import (
CallToolResult,
EmbeddedResource,
ImageContent,
TextContent,
TextResourceContents,
)
from core.model_runtime.entities.llm_entities import LLMUsage
from core.tools.__base.tool_runtime import ToolRuntime
from core.tools.entities.common_entities import I18nObject
from core.tools.entities.tool_entities import ToolEntity, ToolIdentity, ToolInvokeMessage
@@ -120,3 +123,231 @@ class TestMCPToolInvoke:
# Validate values
values = {m.message.variable_name: m.message.variable_value for m in var_msgs}
assert values == {"a": 1, "b": "x"}
class TestMCPToolUsageExtraction:
"""Test usage metadata extraction from MCP tool results."""
def test_extract_usage_dict_from_direct_usage_field(self) -> None:
"""Test extraction when usage is directly in meta.usage field."""
meta = {
"usage": {
"prompt_tokens": 100,
"completion_tokens": 50,
"total_tokens": 150,
"total_price": "0.001",
"currency": "USD",
}
}
usage_dict = MCPTool._extract_usage_dict(meta)
assert usage_dict is not None
assert usage_dict["prompt_tokens"] == 100
assert usage_dict["completion_tokens"] == 50
assert usage_dict["total_tokens"] == 150
assert usage_dict["total_price"] == "0.001"
assert usage_dict["currency"] == "USD"
def test_extract_usage_dict_from_nested_metadata(self) -> None:
"""Test extraction when usage is nested in meta.metadata.usage."""
meta = {
"metadata": {
"usage": {
"prompt_tokens": 200,
"completion_tokens": 100,
"total_tokens": 300,
}
}
}
usage_dict = MCPTool._extract_usage_dict(meta)
assert usage_dict is not None
assert usage_dict["prompt_tokens"] == 200
assert usage_dict["total_tokens"] == 300
def test_extract_usage_dict_from_flat_token_fields(self) -> None:
"""Test extraction when token counts are directly in meta."""
meta = {
"prompt_tokens": 150,
"completion_tokens": 75,
"total_tokens": 225,
"currency": "EUR",
}
usage_dict = MCPTool._extract_usage_dict(meta)
assert usage_dict is not None
assert usage_dict["prompt_tokens"] == 150
assert usage_dict["completion_tokens"] == 75
assert usage_dict["total_tokens"] == 225
assert usage_dict["currency"] == "EUR"
def test_extract_usage_dict_recursive(self) -> None:
"""Test recursive search through nested structures."""
meta = {
"custom": {
"nested": {
"usage": {
"total_tokens": 500,
"prompt_tokens": 300,
"completion_tokens": 200,
}
}
}
}
usage_dict = MCPTool._extract_usage_dict(meta)
assert usage_dict is not None
assert usage_dict["total_tokens"] == 500
def test_extract_usage_dict_from_list(self) -> None:
"""Test extraction from nested list structures."""
meta = {
"items": [
{"usage": {"total_tokens": 100}},
{"other": "data"},
]
}
usage_dict = MCPTool._extract_usage_dict(meta)
assert usage_dict is not None
assert usage_dict["total_tokens"] == 100
def test_extract_usage_dict_returns_none_when_missing(self) -> None:
"""Test that None is returned when no usage data is present."""
meta = {"other": "data", "custom": {"nested": {"value": 123}}}
usage_dict = MCPTool._extract_usage_dict(meta)
assert usage_dict is None
def test_extract_usage_dict_empty_meta(self) -> None:
"""Test with empty meta dict."""
usage_dict = MCPTool._extract_usage_dict({})
assert usage_dict is None
def test_derive_usage_from_result_with_meta(self) -> None:
"""Test _derive_usage_from_result with populated meta."""
meta = {
"usage": {
"prompt_tokens": 100,
"completion_tokens": 50,
"total_tokens": 150,
"total_price": "0.0015",
"currency": "USD",
}
}
result = CallToolResult(content=[], _meta=meta)
usage = MCPTool._derive_usage_from_result(result)
assert isinstance(usage, LLMUsage)
assert usage.prompt_tokens == 100
assert usage.completion_tokens == 50
assert usage.total_tokens == 150
assert usage.total_price == Decimal("0.0015")
assert usage.currency == "USD"
def test_derive_usage_from_result_without_meta(self) -> None:
"""Test _derive_usage_from_result with no meta returns empty usage."""
result = CallToolResult(content=[], meta=None)
usage = MCPTool._derive_usage_from_result(result)
assert isinstance(usage, LLMUsage)
assert usage.total_tokens == 0
assert usage.prompt_tokens == 0
assert usage.completion_tokens == 0
def test_derive_usage_from_result_calculates_total_tokens(self) -> None:
"""Test that total_tokens is calculated when missing."""
meta = {
"usage": {
"prompt_tokens": 100,
"completion_tokens": 50,
# total_tokens is missing
}
}
result = CallToolResult(content=[], _meta=meta)
usage = MCPTool._derive_usage_from_result(result)
assert usage.total_tokens == 150 # 100 + 50
assert usage.prompt_tokens == 100
assert usage.completion_tokens == 50
def test_invoke_sets_latest_usage_from_meta(self) -> None:
"""Test that _invoke sets _latest_usage from result meta."""
tool = _make_mcp_tool()
meta = {
"usage": {
"prompt_tokens": 200,
"completion_tokens": 100,
"total_tokens": 300,
"total_price": "0.003",
"currency": "USD",
}
}
result = CallToolResult(content=[TextContent(type="text", text="test")], _meta=meta)
with patch.object(tool, "invoke_remote_mcp_tool", return_value=result):
list(tool._invoke(user_id="test_user", tool_parameters={}))
# Verify latest_usage was set correctly
assert tool.latest_usage.prompt_tokens == 200
assert tool.latest_usage.completion_tokens == 100
assert tool.latest_usage.total_tokens == 300
assert tool.latest_usage.total_price == Decimal("0.003")
def test_invoke_with_no_meta_returns_empty_usage(self) -> None:
"""Test that _invoke returns empty usage when no meta is present."""
tool = _make_mcp_tool()
result = CallToolResult(content=[TextContent(type="text", text="test")], _meta=None)
with patch.object(tool, "invoke_remote_mcp_tool", return_value=result):
list(tool._invoke(user_id="test_user", tool_parameters={}))
# Verify latest_usage is empty
assert tool.latest_usage.total_tokens == 0
assert tool.latest_usage.prompt_tokens == 0
assert tool.latest_usage.completion_tokens == 0
def test_latest_usage_property_returns_llm_usage(self) -> None:
"""Test that latest_usage property returns LLMUsage instance."""
tool = _make_mcp_tool()
assert isinstance(tool.latest_usage, LLMUsage)
def test_initial_usage_is_empty(self) -> None:
"""Test that MCPTool is initialized with empty usage."""
tool = _make_mcp_tool()
assert tool.latest_usage.total_tokens == 0
assert tool.latest_usage.prompt_tokens == 0
assert tool.latest_usage.completion_tokens == 0
assert tool.latest_usage.total_price == Decimal(0)
@pytest.mark.parametrize(
"meta_data",
[
# Direct usage field
{"usage": {"prompt_tokens": 10, "completion_tokens": 5, "total_tokens": 15}},
# Nested metadata
{"metadata": {"usage": {"total_tokens": 100}}},
# Flat token fields
{"total_tokens": 50, "prompt_tokens": 30, "completion_tokens": 20},
# With price info
{
"usage": {
"total_tokens": 150,
"total_price": "0.002",
"currency": "EUR",
}
},
# Deep nested
{"level1": {"level2": {"usage": {"total_tokens": 200}}}},
],
)
def test_various_meta_formats(self, meta_data) -> None:
"""Test that various meta formats are correctly parsed."""
result = CallToolResult(content=[], _meta=meta_data)
usage = MCPTool._derive_usage_from_result(result)
assert isinstance(usage, LLMUsage)
# Should have at least some usage data
if meta_data.get("usage", {}).get("total_tokens") or meta_data.get("total_tokens"):
expected_total = (
meta_data.get("usage", {}).get("total_tokens")
or meta_data.get("total_tokens")
or meta_data.get("metadata", {}).get("usage", {}).get("total_tokens")
or meta_data.get("level1", {}).get("level2", {}).get("usage", {}).get("total_tokens")
)
if expected_total:
assert usage.total_tokens == expected_total