Pydantic AI

Pydantic AI is a Python agent framework from the Pydantic team. Its capability library, Pydantic AI Harness, includes two capabilities backed by You.com APIs:

• YouSearch adds web_search (Web Search API) and get_page (Contents API).
• YouResearch adds answer (Answer API), research (Research API), and finance_research (Finance Research API).

Each tool returns a Sources: block the model can cite, plus the same sources as structured metadata for your code.

Getting Started

pip install "pydantic-ai-harness[youdotcom,anthropic]"

export YDC_API_KEY="<YDC_API_KEY>"
export ANTHROPIC_API_KEY="<ANTHROPIC_API_KEY>"

Usage

from pydantic_ai import Agent
from pydantic_ai_harness import YouResearch, YouSearch
agent = Agent('anthropic:claude-sonnet-4-6', capabilities=[YouSearch(), YouResearch()])
result = agent.run_sync('What changed in the latest stable Python release?')
print(result.output)

The Pydantic AI Harness reference lists every field and covers custom clients, multiple instances, native search fallback, and YAML agent specs.

Tools

Each tool call is billed at the rate of its underlying API.

Error Handling

The error code reference lists what each status means.

Durable Execution

Under Temporal, Prefect, or DBOS, each You.com request is recorded under the capability id (you_search or you_research), so a recovered run reuses the result instead of calling the API again. Keep the id stable once deployed—renaming it breaks in-flight runs.

A Temporal activity times out after 60 seconds by default, which research can exceed. Give the you_research toolset more time:

from datetime import timedelta
from pydantic_ai.durable_exec.temporal import TemporalDurability
from temporalio.workflow import ActivityConfig
TemporalDurability(
    toolset_activity_config={
        'you_research': ActivityConfig(start_to_close_timeout=timedelta(minutes=10)),
    },
)

Cookbook

The pydantic-cookbook repo has four runnable examples:

git clone https://github.com/youdotcom-oss/pydantic-cookbook
cd pydantic-cookbook
python -m venv .venv && source .venv/bin/activate
pip install -r requirements.txt
cp .env.example .env   # add YDC_API_KEY and OPENROUTER_API_KEY
make smoke             # builds every agent without network calls
make run-edu           # or run-health, run-finance, run-deal

Resources