Add tool approval integration for Vercel AI adapter

pydantic_ai_slim/pydantic_ai/ui/vercel_ai/_adapter.py

@@ -35,7 +35,7 @@
     VideoUrl,
 )
 from ...output import OutputDataT
-from ...tools import AgentDepsT
+from ...tools import AgentDepsT, DeferredToolResults, ToolApproved, ToolDenied
 from .. import MessagesBuilder, UIAdapter, UIEventStream
 from ._event_stream import VercelAIEventStream
 from .request_types import (
@@ -51,6 +51,7 @@
     SourceUrlUIPart,
     StepStartUIPart,
     TextUIPart,
+    ToolApprovalResponded,
     ToolInputAvailablePart,
     ToolOutputAvailablePart,
     ToolOutputErrorPart,
@@ -87,6 +88,56 @@ def messages(self) -> list[ModelMessage]:
         """Pydantic AI messages from the Vercel AI run input."""
         return self.load_messages(self.run_input.messages)
 
+    @cached_property
+    def deferred_tool_results(self) -> DeferredToolResults | None:
+        """Extract deferred tool results from tool parts with approval responses.
+
+        When the Vercel AI SDK client responds to a tool-approval-request, it sends
+        the approval decision in the tool part's `approval` field. This method extracts
+        those responses and converts them to Pydantic AI's `DeferredToolResults` format.
+
+        Returns:
+            DeferredToolResults if any tool parts have approval responses, None otherwise.
+        """
+        return self.extract_deferred_tool_results(self.run_input.messages)
+
+    @classmethod
+    def extract_deferred_tool_results(cls, messages: Sequence[UIMessage]) -> DeferredToolResults | None:
+        """Extract deferred tool results from UI messages.
+
+        Args:
+            messages: The UI messages to scan for approval responses.
+
+        Returns:
+            DeferredToolResults if any tool parts have approval responses, None otherwise.
+        """
+        approvals: dict[str, bool | ToolApproved | ToolDenied] = {}
+
+        for msg in messages:
+            if msg.role != 'assistant':
+                continue
+
+            for part in msg.parts:
+                if not isinstance(part, ToolUIPart | DynamicToolUIPart):
+                    continue
+
+                approval = part.approval
+                if approval is None or not isinstance(approval, ToolApprovalResponded):
+                    continue
+
+                tool_call_id = part.tool_call_id
+                if approval.approved:
+                    approvals[tool_call_id] = ToolApproved()
+                else:
+                    approvals[tool_call_id] = ToolDenied(
+                        message=approval.reason or 'The tool call was denied.'
+                    )
+
+        if not approvals:
+            return None
+
+        return DeferredToolResults(approvals=approvals)
+
     @classmethod
     def load_messages(cls, messages: Sequence[UIMessage]) -> list[ModelMessage]:  # noqa: C901
         """Transform Vercel AI messages into Pydantic AI messages."""

pydantic_ai_slim/pydantic_ai/ui/vercel_ai/_event_stream.py

@@ -5,6 +5,7 @@
 from collections.abc import AsyncIterator, Mapping
 from dataclasses import dataclass
 from typing import Any
+from uuid import uuid4
 
 from pydantic_core import to_json
 
@@ -13,6 +14,7 @@
     BuiltinToolCallPart,
     BuiltinToolReturnPart,
     FilePart,
+    FinishReason as PydanticFinishReason,
     FunctionToolResultEvent,
     RetryPromptPart,
     TextPart,
@@ -23,7 +25,8 @@
     ToolCallPartDelta,
 )
 from ...output import OutputDataT
-from ...tools import AgentDepsT
+from ...run import AgentRunResultEvent
+from ...tools import AgentDepsT, DeferredToolRequests
 from .. import UIEventStream
 from .request_types import RequestData
 from .response_types import (
@@ -32,6 +35,7 @@
     ErrorChunk,
     FileChunk,
     FinishChunk,
+    FinishReason,
     FinishStepChunk,
     ReasoningDeltaChunk,
     ReasoningEndChunk,
@@ -41,13 +45,23 @@
     TextDeltaChunk,
     TextEndChunk,
     TextStartChunk,
+    ToolApprovalRequestChunk,
     ToolInputAvailableChunk,
     ToolInputDeltaChunk,
     ToolInputStartChunk,
     ToolOutputAvailableChunk,
     ToolOutputErrorChunk,
 )
 
+# Map Pydantic AI finish reasons to Vercel AI format
+_FINISH_REASON_MAP: dict[PydanticFinishReason, FinishReason] = {
+    'stop': 'stop',
+    'length': 'length',
+    'content_filter': 'content-filter',
+    'tool_call': 'tool-calls',
+    'error': 'error',
+}
+
 __all__ = ['VercelAIEventStream']
 
 # See https://ai-sdk.dev/docs/ai-sdk-ui/stream-protocol#data-stream-protocol
@@ -64,6 +78,7 @@ class VercelAIEventStream(UIEventStream[RequestData, BaseChunk, AgentDepsT, Outp
     """UI event stream transformer for the Vercel AI protocol."""
 
     _step_started: bool = False
+    _finish_reason: FinishReason = None
 
     @property
     def response_headers(self) -> Mapping[str, str] | None:
@@ -85,10 +100,25 @@ async def before_response(self) -> AsyncIterator[BaseChunk]:
     async def after_stream(self) -> AsyncIterator[BaseChunk]:
         yield FinishStepChunk()
 
-        yield FinishChunk()
+        yield FinishChunk(finish_reason=self._finish_reason)
         yield DoneChunk()
 
+    async def handle_run_result(self, event: AgentRunResultEvent) -> AsyncIterator[BaseChunk]:
+        pydantic_reason = event.result.response.finish_reason
+        if pydantic_reason:
+            self._finish_reason = _FINISH_REASON_MAP.get(pydantic_reason)
+
+        # Emit tool approval requests for deferred approvals
+        output = event.result.output
+        if isinstance(output, DeferredToolRequests):
+            for tool_call in output.approvals:
+                yield ToolApprovalRequestChunk(
+                    approval_id=str(uuid4()),
+                    tool_call_id=tool_call.tool_call_id,
+                )
+
     async def on_error(self, error: Exception) -> AsyncIterator[BaseChunk]:
+        self._finish_reason = 'error'
         yield ErrorChunk(error_text=str(error))
 
     async def handle_text_start(self, part: TextPart, follows_text: bool = False) -> AsyncIterator[BaseChunk]:

pydantic_ai_slim/pydantic_ai/ui/vercel_ai/request_types.py

@@ -110,6 +110,30 @@ class DataUIPart(BaseUIPart):
     data: Any
 
 
+class ToolApprovalRequested(CamelBaseModel):
+    """Tool approval in requested state (awaiting user response)."""
+
+    id: str
+    """The approval request ID."""
+
+
+class ToolApprovalResponded(CamelBaseModel):
+    """Tool approval in responded state (user has approved or denied)."""
+
+    id: str
+    """The approval request ID."""
+
+    approved: bool
+    """Whether the user approved the tool call."""
+
+    reason: str | None = None
+    """Optional reason for the approval or denial."""
+
+
+ToolApproval = ToolApprovalRequested | ToolApprovalResponded
+"""Union of tool approval states."""
+
+
 # Tool part states as separate models
 class ToolInputStreamingPart(BaseUIPart):
     """Tool part in input-streaming state."""
@@ -119,6 +143,7 @@ class ToolInputStreamingPart(BaseUIPart):
     state: Literal['input-streaming'] = 'input-streaming'
     input: Any | None = None
     provider_executed: bool | None = None
+    approval: ToolApproval | None = None
 
 
 class ToolInputAvailablePart(BaseUIPart):
@@ -130,6 +155,7 @@ class ToolInputAvailablePart(BaseUIPart):
     input: Any | None = None
     provider_executed: bool | None = None
     call_provider_metadata: ProviderMetadata | None = None
+    approval: ToolApproval | None = None
 
 
 class ToolOutputAvailablePart(BaseUIPart):
@@ -143,6 +169,7 @@ class ToolOutputAvailablePart(BaseUIPart):
     provider_executed: bool | None = None
     call_provider_metadata: ProviderMetadata | None = None
     preliminary: bool | None = None
+    approval: ToolApproval | None = None
 
 
 class ToolOutputErrorPart(BaseUIPart):
@@ -156,6 +183,7 @@ class ToolOutputErrorPart(BaseUIPart):
     error_text: str
     provider_executed: bool | None = None
     call_provider_metadata: ProviderMetadata | None = None
+    approval: ToolApproval | None = None
 
 
 ToolUIPart = ToolInputStreamingPart | ToolInputAvailablePart | ToolOutputAvailablePart | ToolOutputErrorPart
@@ -171,6 +199,7 @@ class DynamicToolInputStreamingPart(BaseUIPart):
     tool_call_id: str
     state: Literal['input-streaming'] = 'input-streaming'
     input: Any | None = None
+    approval: ToolApproval | None = None
 
 
 class DynamicToolInputAvailablePart(BaseUIPart):
@@ -182,6 +211,7 @@ class DynamicToolInputAvailablePart(BaseUIPart):
     state: Literal['input-available'] = 'input-available'
     input: Any
     call_provider_metadata: ProviderMetadata | None = None
+    approval: ToolApproval | None = None
 
 
 class DynamicToolOutputAvailablePart(BaseUIPart):
@@ -195,6 +225,7 @@ class DynamicToolOutputAvailablePart(BaseUIPart):
     output: Any
     call_provider_metadata: ProviderMetadata | None = None
     preliminary: bool | None = None
+    approval: ToolApproval | None = None
 
 
 class DynamicToolOutputErrorPart(BaseUIPart):
@@ -207,6 +238,7 @@ class DynamicToolOutputErrorPart(BaseUIPart):
     input: Any
     error_text: str
     call_provider_metadata: ProviderMetadata | None = None
+    approval: ToolApproval | None = None
 
 
 DynamicToolUIPart = (

pydantic_ai_slim/pydantic_ai/ui/vercel_ai/response_types.py

@@ -16,6 +16,9 @@
 ProviderMetadata = dict[str, dict[str, JSONValue]]
 """Provider metadata."""
 
+FinishReason = Literal['stop', 'length', 'content-filter', 'tool-calls', 'error', 'other', 'unknown'] | None
+"""Reason why the model finished generating."""
+
 
 class BaseChunk(CamelBaseModel, ABC):
     """Abstract base class for response SSE events."""
@@ -145,6 +148,21 @@ class ToolOutputErrorChunk(BaseChunk):
     dynamic: bool | None = None
 
 
+class ToolApprovalRequestChunk(BaseChunk):
+    """Tool approval request chunk for human-in-the-loop approval."""
+
+    type: Literal['tool-approval-request'] = 'tool-approval-request'
+    approval_id: str
+    tool_call_id: str
+
+
+class ToolOutputDeniedChunk(BaseChunk):
+    """Tool output denied chunk when user denies tool execution."""
+
+    type: Literal['tool-output-denied'] = 'tool-output-denied'
+    tool_call_id: str
+
+
 class SourceUrlChunk(BaseChunk):
     """Source URL chunk."""
 
@@ -178,7 +196,9 @@ class DataChunk(BaseChunk):
     """Data chunk with dynamic type."""
 
     type: Annotated[str, Field(pattern=r'^data-')]
+    id: str | None = None
     data: Any
+    transient: bool | None = None
 
 
 class StartStepChunk(BaseChunk):
@@ -205,6 +225,7 @@ class FinishChunk(BaseChunk):
     """Finish chunk."""
 
     type: Literal['finish'] = 'finish'
+    finish_reason: FinishReason = None
     message_metadata: Any | None = None