feat: add client side tools to bridge and new cas events by norman-le · Pull Request #1609 · UiPath/uipath-python

norman-le · 2026-05-01T21:15:47Z

## uipath-python

- Added ClientSide tool type to agent model so the runtime can distinguish client-side tools from server tools
- Bridge emits executingToolCall event on durable interrupt when is_execution_phase marker is set, enabling the client to know when to execute the tool
- Bridge routes endToolCall from the client back to the agent, completing the interrupt/resume cycle

## uipath-langchain-python

- Client-side tool factory creates StructuredTool instances that use @durable_interrupt to pause the graph and wait for client execution
- @mockable wraps @durable_interrupt (as a separate outer function) so evals can simulate client-side tools without hitting GraphInterrupt
- CLIENT_SIDE_TOOL_MARKER defined in hitl.py as the single source of truth for identifying client-side tools across the codebase
- Error-handling wrapper (RunnableCallableWithTool) now preserves .tool reference for client-side tools, enabling runtime discovery
- Runtime discovers client-side tools from the compiled graph via shared _iter_graph_tools() iterator, used by both confirmation and client-side tool detection
- MessageMapper emits executingToolCall only for server tools without interrupts; client-side and confirmation tools get it from the bridge instead
- MessageMapper suppresses endToolCall for client-side tool results since the client already produced the result
- MessageMapper sets isClientSideTool and outputSchema on startToolCall events so the client knows to show the input form
- 9 new tests covering tool discovery, executingToolCall emission rules, and endToolCall suppression

## uipath-agents-python

- Graph builder strips CLIENT_SIDE_TOOL_MARKER during evals so @durable_interrupt is bypassed and @mockable can intercept

## AgentInterfaces

- CAS tracks is_client_side_tool on tool calls in the database and forwards client-originated endToolCall to the agent
- CAS validates client-side tool declarations against the agent definition and guards against unauthorized endToolCall for non-client-side tools
- React SDK listens for executingToolCall events and renders a form (ClientSideToolWidget) using the tool's output schema for the user to fill in
- ClientSideToolWidget reuses the existing ToolConfirmationFormContent component
- Added type schemas for executingToolCall events and client-side tool declarations

Videos in CAS localhost (Agent Builder changes already published, but this will be the debug experience as well when the sdk is upgraded):

Without tool confirmation for client side tool:

Screen.Recording.2026-05-13.at.9.32.26.PM.mov

With tool confirmation for client side tool:

Screen.Recording.2026-05-13.at.9.27.56.PM.mov

URT Eval:

Related to changes in other PRs:
CAS: https://github.com/UiPath/AgentInterfaces/pull/949
uipath-langchain-python (tool definition): UiPath/uipath-langchain-python#819
uipath-python (bridge changes): #1609
uipath-agents-python (skipping for evals, so it can be mocked): https://github.com/UiPath/uipath-agents-python/pull/485
Another Agents PR fixing some issues with debug: https://github.com/UiPath/Agents/pull/5250

Copilot

Pull request overview

Adds support for “client-side tools” in agent resource modeling and extends the chat event protocol/bridge to handle additional tool-call lifecycle events (including an executingToolCall signal and new CAS event handling paths).

Changes:

Add ClientSide as a new AgentToolType and introduce AgentClientSideToolResourceConfig, including normalization support.
Extend core chat tool-call event models with executingToolCall and additional start-event fields (isClientSideTool, outputSchema).
Update the CLI Socket.IO chat bridge to parse endToolCall as a resume signal and add an emitter for executingToolCall.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
packages/uipath/src/uipath/agent/models/agent.py	Adds a new agent tool type + resource config union member and normalizes incoming tool type strings for client-side tools.
packages/uipath/src/uipath/_cli/_chat/_bridge.py	Adds support for new CAS tool-call event shapes and introduces an `executingToolCall` emitter based on resume triggers.
packages/uipath-core/src/uipath/core/chat/tool.py	Extends the chat protocol models with `executingToolCall` and new start-event fields to represent client-side tools.
packages/uipath-core/src/uipath/core/chat/init.py	Exports the newly added `UiPathConversationExecutingToolCallEvent`.

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+        tool_call_id = request.get("tool_call_id")
+        tool_name = request.get("tool_name")
+        tool_input = request.get("input")
+
+        if not tool_call_id or not tool_name:
+            logger.info(
+                f"emit_executing_tool_call_event: missing tool_call_id or tool_name, skipping. tool_call_id={tool_call_id}, tool_name={tool_name}"
+            )
+            return
+
+        executing_event = UiPathConversationMessageEvent(
+            message_id=self._current_message_id,
+            tool_call=UiPathConversationToolCallEvent(
+                tool_call_id=tool_call_id,
+                executing=UiPathConversationExecutingToolCallEvent(
+                    tool_name=tool_name,
+                    input=tool_input,
+                ),


        self._tool_confirmation_event = asyncio.Event()
        self._tool_confirmation_value: (
-            UiPathConversationToolCallConfirmationEvent | None
+            UiPathConversationToolCallConfirmationEvent
+            | UiPathConversationToolCallEndEvent
+            | None
        ) = None


+class AgentClientSideToolResourceConfig(BaseAgentToolResourceConfig):
+    """Resource config for client-side tools executed by the client SDK."""
+
+    type: Literal[AgentToolType.CLIENT_SIDE] = AgentToolType.CLIENT_SIDE
+    properties: BaseResourceProperties = Field(default_factory=BaseResourceProperties)
+    output_schema: Optional[Dict[str, Any]] = Field(None, alias="outputSchema")
+    arguments: Optional[Dict[str, Any]] = Field(default_factory=dict)
+


JoshParkSJ · 2026-05-10T02:25:14Z

+class AgentClientSideToolResourceConfig(BaseAgentToolResourceConfig):
+    """Resource config for client-side tools executed by the client SDK."""
+
+    type: Literal[AgentToolType.CLIENT_SIDE] = AgentToolType.CLIENT_SIDE


Can we add an example maybe in agentinterfaces what an example client side tool would look like?

sonarqubecloud · 2026-05-14T01:39:44Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
91.7% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

feat: add client side tools to bridge and new cas events

4fc2ad4

Copilot AI review requested due to automatic review settings May 1, 2026 21:15

github-actions Bot added test:uipath-langchain Triggers tests in the uipath-langchain-python repository test:uipath-runtime test:uipath-integrations labels May 1, 2026

Copilot started reviewing on behalf of norman-le May 1, 2026 21:16 View session

Copilot AI reviewed May 1, 2026

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JoshParkSJ reviewed May 10, 2026

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chore: update to use existing interrupt event and update comments

39919b2

norman-le mentioned this pull request May 14, 2026

feat: add client side tools to mapper and runtime UiPath/uipath-langchain-python#819

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feat: add client side tools to bridge and new cas events#1609

feat: add client side tools to bridge and new cas events#1609
norman-le wants to merge 2 commits into
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feat/jar-9629-client-side-tools-cas-urt

norman-le commented May 1, 2026 •

edited

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sonarqubecloud Bot commented May 14, 2026

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norman-le commented May 1, 2026 •

edited

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