feat: add Pydantic AI sync streaming converter

Introduces convert_pydantic_ai_to_agentex_events at
agentex.lib.adk.providers._modules.pydantic_ai, mirroring the existing
OpenAI Agents SDK converter in sync_provider.py. Maps Pydantic AI's
AgentStreamEvent stream (PartStartEvent / PartDeltaEvent / PartEndEvent
/ FunctionToolResultEvent) into Agentex StreamTaskMessage* events,
with first-class support for tool-call argument tokens streaming via
ToolCallPartDelta.args_delta -> ToolRequestDelta.arguments_delta.

This is slice 1 of an Agentex <-> Pydantic AI integration intended to
match the level of support we have for OpenAI Agents SDK (sync,
non-Temporal async, and Temporal). Subsequent slices will add the
example agent, tracing wiring, and CLI templates.

Adds pydantic-ai-slim>=1.0,<2 as a hard dependency, consistent with
how openai-agents and other framework integrations are pinned.

22 unit tests cover text streaming, tool-call delta streaming,
multi-step runs (where Pydantic AI part indices restart at 0 per
model response), thinking/reasoning deltas, structured one-shot args,
RetryPromptPart results, and ignored events.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: danielmillerp

pyproject.toml

@@ -36,6 +36,7 @@ dependencies = [
     "mcp[cli]>=1.4.1",
     "scale-gp>=0.1.0a59",
     "openai-agents==0.14.1",
+    "pydantic-ai-slim>=1.0,<2",
     "tzlocal>=5.3.1",
     "tzdata>=2025.2",
     "pytest>=8.4.0",

requirements-dev.lock

@@ -112,10 +112,13 @@ frozenlist==1.8.0
     # via aiosignal
 fsspec==2026.3.0
     # via huggingface-hub
+genai-prices==0.0.59
+    # via pydantic-ai-slim
 google-auth==2.49.1
     # via kubernetes
 griffelib==2.0.2
     # via openai-agents
+    # via pydantic-ai-slim
 h11==0.16.0
     # via httpcore
     # via uvicorn
@@ -126,12 +129,15 @@ httpcore==1.0.9
 httpx==0.28.1
     # via agentex-sdk
     # via anthropic
+    # via genai-prices
     # via httpx-aiohttp
     # via huggingface-hub
     # via langsmith
     # via litellm
     # via mcp
     # via openai
+    # via pydantic-ai-slim
+    # via pydantic-graph
     # via respx
     # via scale-gp
     # via scale-gp-beta
@@ -196,6 +202,8 @@ langsmith==0.7.22
     # via langchain-core
 litellm==1.83.7
     # via agentex-sdk
+logfire-api==4.32.1
+    # via pydantic-graph
 markdown-it-py==3.0.0
     # via rich
 markupsafe==3.0.3
@@ -236,6 +244,7 @@ opentelemetry-api==1.40.0
     # via ddtrace
     # via opentelemetry-sdk
     # via opentelemetry-semantic-conventions
+    # via pydantic-ai-slim
 opentelemetry-sdk==1.40.0
     # via agentex-sdk
 opentelemetry-semantic-conventions==0.61b0
@@ -287,18 +296,25 @@ pydantic==2.12.5
     # via agentex-sdk
     # via anthropic
     # via fastapi
+    # via genai-prices
     # via langchain-core
     # via langsmith
     # via litellm
     # via mcp
     # via openai
     # via openai-agents
+    # via pydantic-ai-slim
+    # via pydantic-graph
     # via pydantic-settings
     # via python-on-whales
     # via scale-gp
     # via scale-gp-beta
+pydantic-ai-slim==1.92.0
+    # via agentex-sdk
 pydantic-core==2.41.5
     # via pydantic
+pydantic-graph==1.92.0
+    # via pydantic-ai-slim
 pydantic-settings==2.13.1
     # via mcp
 pygments==2.19.2
@@ -459,6 +475,8 @@ typing-inspection==0.4.2
     # via fastapi
     # via mcp
     # via pydantic
+    # via pydantic-ai-slim
+    # via pydantic-graph
     # via pydantic-settings
 tzdata==2025.3
     # via agentex-sdk

requirements.lock

@@ -99,10 +99,13 @@ frozenlist==1.8.0
     # via aiosignal
 fsspec==2026.3.0
     # via huggingface-hub
+genai-prices==0.0.59
+    # via pydantic-ai-slim
 google-auth==2.49.1
     # via kubernetes
 griffelib==2.0.2
     # via openai-agents
+    # via pydantic-ai-slim
 h11==0.16.0
     # via httpcore
     # via uvicorn
@@ -113,12 +116,15 @@ httpcore==1.0.9
 httpx==0.28.1
     # via agentex-sdk
     # via anthropic
+    # via genai-prices
     # via httpx-aiohttp
     # via huggingface-hub
     # via langsmith
     # via litellm
     # via mcp
     # via openai
+    # via pydantic-ai-slim
+    # via pydantic-graph
     # via scale-gp
     # via scale-gp-beta
 httpx-aiohttp==0.1.12
@@ -180,6 +186,8 @@ langsmith==0.7.22
     # via langchain-core
 litellm==1.83.7
     # via agentex-sdk
+logfire-api==4.32.1
+    # via pydantic-graph
 markdown-it-py==4.0.0
     # via rich
 markupsafe==3.0.3
@@ -214,6 +222,7 @@ opentelemetry-api==1.40.0
     # via ddtrace
     # via opentelemetry-sdk
     # via opentelemetry-semantic-conventions
+    # via pydantic-ai-slim
 opentelemetry-sdk==1.40.0
     # via agentex-sdk
 opentelemetry-semantic-conventions==0.61b0
@@ -260,18 +269,25 @@ pydantic==2.12.5
     # via agentex-sdk
     # via anthropic
     # via fastapi
+    # via genai-prices
     # via langchain-core
     # via langsmith
     # via litellm
     # via mcp
     # via openai
     # via openai-agents
+    # via pydantic-ai-slim
+    # via pydantic-graph
     # via pydantic-settings
     # via python-on-whales
     # via scale-gp
     # via scale-gp-beta
+pydantic-ai-slim==1.92.0
+    # via agentex-sdk
 pydantic-core==2.41.5
     # via pydantic
+pydantic-graph==1.92.0
+    # via pydantic-ai-slim
 pydantic-settings==2.13.1
     # via mcp
 pygments==2.20.0
@@ -424,6 +440,8 @@ typing-inspection==0.4.2
     # via fastapi
     # via mcp
     # via pydantic
+    # via pydantic-ai-slim
+    # via pydantic-graph
     # via pydantic-settings
 tzdata==2025.3
     # via agentex-sdk