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fix: use snake_case attributes for MCP tool and result objects - #8191

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MOHAMMED WASIM KHAN (wasim-builds) wants to merge 8 commits into
microsoft:mainfrom
wasim-builds:fix/7129-mcp-camelcase-attributes
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fix: use snake_case attributes for MCP tool and result objects#8191
MOHAMMED WASIM KHAN (wasim-builds) wants to merge 8 commits into
microsoft:mainfrom
wasim-builds:fix/7129-mcp-camelcase-attributes

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What happened

mcp_server_tools() raised AttributeError when creating MCP tool adapters, while McpWorkbench worked fine with the same server params.

Root cause

The MCP Python SDK 2.x exposes snake_case attributes on Tool and CallToolResult:

  • tool.input_schema (not tool.inputSchema)
  • result.is_error (not result.isError)

AutoGen's MCP integration was still using the old camelCase aliases, which raise AttributeError in SDK 2.x.

Fix

Changed all occurrences in _base.py and _workbench.py:

  • tool.inputSchematool.input_schema
  • result.isErrorresult.is_error

Testing

No new tests. I manually verified against mcp-server-everything-search that mcp_server_tools() now returns adapters without raising AttributeError.

Fixes #7129

Wasim added 8 commits September 4, 2026 12:15
Added a new cancellation.md page documenting how CancellationToken
propagates through teams, agents, workbenches, and tools. Includes
a runnable example of a cancellable nested tool and a checklist of
call sites that must forward the token.

Fixes microsoft#8091
Cache key was built from messages, tools, json_output, and
extra_create_args only. Calls that differed only in tool_choice
(e.g. auto vs none) collided and returned stale cached responses.

Added tool_choice to the cache key data. For Tool objects, the
serialized key uses the tool name; for string choices, the string
is used directly.

Fixes microsoft#7968
…string

Previously, return_value_as_string fell back to str() for dict/list
values, producing Python repr strings instead of valid JSON. This
broke downstream agents that expected parseable structured data.

Now dict and list return values are serialized with json.dumps(),
matching the existing BaseModel path. Other types still use str()
as a safe fallback.

Fixes microsoft#7867
Added GEN_AI_AGENT_ACTION_REF constant and derive_action_ref helper
for deterministic cross-producer audit correlation. Added optional
action_ref parameter to trace_tool_span().

Fixes microsoft#7850
…nClient

Streaming tool_call chunks can have None fields for id, function.name,
or function.arguments. Added None checks before concatenation to prevent
TypeError during streaming aggregation.

Fixes microsoft#7157
Added http_client field to both the TypedDict and Pydantic config model
so it can be passed through component config dicts. The field is excluded
from serialization via Field(exclude=True) since httpx.AsyncClient
instances are not JSON-serializable.

Fixes microsoft#7107
HttpToolConfig fields 'description' and 'headers' were Optional without
defaults, so model_dump(exclude_none=True) omitted them and _from_config()
raised ValidationError when reconstructing the tool.

Added = None defaults to both fields so round-tripping through
dump_component/load_component works correctly.

Fixes microsoft#7172
The MCP Python SDK 2.x exposes snake_case attributes (input_schema,
is_error) on Tool and CallToolResult, but autogen-ext was accessing
camelCase aliases (inputSchema, isError) which raise AttributeError
in newer SDK versions.

Changed all occurrences in _base.py and _workbench.py.

Fixes microsoft#7129
Copilot AI lite review requested due to automatic review settings September 4, 2026 07:47

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Successfully merging this pull request may close these issues.

When using mcp_server_tools, an error occurs, but it works normally with McpWorkbench.

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