---
name: pydantic-ai-expert
description: "Expert guide for type-safe Python AI agent development with Pydantic AI — dependency injection, structured outputs, model-agnostic routing, and graph workflows / Panduan ahli pengembangan agen AI Python type-safe dengan Pydantic AI."
author: "Roedy Rustam"
version: "4.4.2"

---

# Pydantic AI Expert (Type-Safe Python Agent Engineering)

[English](#english) | [Bahasa Indonesia](#bahasa-indonesia)

---

<a name="english"></a>
## English

### Orchestration & Integration
- **Python Language & Runtime**: `python-programming-expert`, `structured-output-contracts`
- **Agent Frameworks & Swarms**: `multi-agent-orchestration`, `ai-llm-integration-expert`, `frontier-ai-models-expert`
- **MCP & Tool Protocols**: `mcp-server-architect`, `parallel-tool-orchestrator`
- **Persistence & Databases**: `database-orm-expert`, `vector-db-rag-expert`
- **Evaluation & Testing**: `autonomous-tdd-debugger`, `property-mutation-testing-expert`, `anti-slop`
- **Lifecycle & Governance**: `zero-to-prod-orchestrator`, `session-memory-manager`

### Description
Production-grade guide for building enterprise AI agents using **Pydantic AI** (from the creators of Pydantic). Unlike untyped or fragile agent libraries, Pydantic AI provides strict static typing (`Agent[DepsType, ReturnType]`), first-class dependency injection (`RunContext[Deps]`), automatic tool parameter validation via Pydantic v2 schemas, model-agnostic provider switching (Anthropic, OpenAI, Gemini, Groq, Ollama), dynamic system prompts, and deterministic structured outputs.

**Swarm Synergy:** Within the **Backend & APIs Swarm**, this skill serves as the Lead Python Agent Engineer. It executes critical business operations, runs data pipelines, and integrates with SQL databases with compile-time type safety in Phase 4.

### Trigger Conditions
- Engineering Python-based autonomous agents requiring strict type safety and schema validation.
- Implementing dependency injection (passing database connections, API clients, or user sessions) into agent tools.
- Extracting guaranteed structured outputs from frontier reasoning models without JSON parsing errors.
- Designing multi-agent delegation or agent handoffs in Python microservices.
- Running unit tests and deterministic evals on agent logic using mock models (`TestModel`).

### Pydantic AI Architecture

```
┌─────────────────────────────────────────────────────────────┐
│                    AGENT DEFINITION                         │
│  Agent[DatabaseDeps, AuditReport](                          │
│    model='anthropic:claude-3-7-sonnet-latest',              │
│    result_type=AuditReport,                                 │
│  )                                                          │
└──────────────────────────────┬──────────────────────────────┘
                               │
       ┌───────────────────────┴───────────────────────┐
       ▼                                               ▼
┌──────────────────────────────┐       ┌──────────────────────────────┐
│     DEPENDENCY INJECTION     │       │     TOOL EXECUTION LOOP      │
│  RunContext[DatabaseDeps]    │       │  @agent.tool                 │
│  • Async DB connection pool  │       │  • Auto Pydantic validation  │
│  • Tenant & session auth     │       │  • Structured error return   │
└──────────────────────────────┘       └──────────────────────────────┘
                               │
                               ▼
┌─────────────────────────────────────────────────────────────┐
│             DETERMINISTIC STRUCTURED RESULT                 │
│  result.data -> Pydantic BaseModel instance (Validated)     │
└─────────────────────────────────────────────────────────────┘
```

### Core Implementation Guidelines

#### 1. Type-Safe Agent with Dependency Injection
Pass database pools or HTTP clients directly into tools without global state:
```python
from dataclasses import dataclass
import asyncpg
from pydantic import BaseModel, Field
from pydantic_ai import Agent, RunContext

@dataclass
class DatabaseDeps:
    pool: asyncpg.Pool
    tenant_id: str

class UserAnomalyReport(BaseModel):
    user_id: str
    risk_score: float = Field(ge=0.0, le=1.0)
    anomalous_events: list[str]
    action_recommended: str

# Typed agent: Agent[DependencyType, ResultType]
security_agent = Agent[DatabaseDeps, UserAnomalyReport](
    model='google-gla:gemini-2.5-flash',
    result_type=UserAnomalyReport,
    system_prompt=(
        "You are an automated SecOps auditor. Analyze the user access logs provided "
        "and generate a strictly structured anomaly assessment."
    ),
)

@security_agent.system_prompt
async def add_tenant_context(ctx: RunContext[DatabaseDeps]) -> str:
    return f"Active Tenant ID: {ctx.deps.tenant_id}. Only audit records matching this tenant."

@security_agent.tool
async def query_audit_logs(ctx: RunContext[DatabaseDeps], user_id: str, limit: int = 50) -> list[dict]:
    """Retrieve raw authentication events for a given user from the audit store."""
    async with ctx.deps.pool.acquire() as conn:
        rows = await conn.fetch(
            "SELECT event_time, ip_address, action, status FROM audit_logs "
            "WHERE tenant_id = $1 AND user_id = $2 ORDER BY event_time DESC LIMIT $3",
            ctx.deps.tenant_id, user_id, limit
        )
        return [dict(r) for r in rows]

# Execution:
async def run_audit(pool: asyncpg.Pool, tenant_id: str, target_user: str) -> UserAnomalyReport:
    deps = DatabaseDeps(pool=pool, tenant_id=tenant_id)
    result = await security_agent.run(f"Audit user activity for {target_user}", deps=deps)
    return result.data  # Guaranteed instance of UserAnomalyReport
```

#### 2. Model-Agnostic Switching & Local SLM Fallback
Pydantic AI allows switching between cloud APIs and local Ollama models effortlessly:
```python
import os
from pydantic_ai.models.anthropic import AnthropicModel
from pydantic_ai.models.ollama import OllamaModel

def get_agent_model():
    if os.getenv("ENV") == "production":
        return AnthropicModel('claude-3-7-sonnet-20250219')
    else:
        # Zero cost local development with Ollama
        return OllamaModel(model_name='qwen2.5-coder:7b')
```

#### 3. Deterministic Testing with `TestModel`
Write unit tests that verify tool invocations and structured output parsing without calling live LLMs:
```python
import pytest
from pydantic_ai.models.test import TestModel

@pytest.mark.asyncio
async def test_security_agent_tool_dispatch():
    # TestModel can simulate deterministic responses or tool calls
    test_model = TestModel(call_tools=['query_audit_logs'])
    
    with security_agent.override(model=test_model):
        deps = DatabaseDeps(pool=mock_pool, tenant_id="tenant_123")
        result = await security_agent.run("Audit user 456", deps=deps)
        assert result.data is not None
```

#### 4. Streaming Structured Output Validation (`run_stream`)
Stream typed Pydantic models with real-time field-level validation as tokens arrive:
```python
from pydantic import BaseModel, Field
from pydantic_ai import Agent

class IncidentTriage(BaseModel):
    severity: str = Field(description="Low, Medium, High, or Critical")
    affected_components: list[str] = Field(default_factory=list)
    immediate_actions: list[str] = Field(default_factory=list)
    root_cause_hypothesis: str

triage_agent = Agent[None, IncidentTriage](
    model='google-gla:gemini-2.5-flash',
    result_type=IncidentTriage,
    system_prompt="You are a real-time site reliability incident responder."
)

async def stream_incident_triage(incident_log: str):
    async with triage_agent.run_stream(f"Triage incident: {incident_log}") as response:
        async for partial_triage in response.stream_structured():
            print(f"[Streaming Partial Validation] Severity: {partial_triage.severity}, Actions: {len(partial_triage.immediate_actions)}")
        
        final_result = await response.get_data()
        return final_result
```

#### 5. Multi-Agent Delegation & Handoffs via `RunContext`
Sub-agents invoked as specialized tools with context isolation:
```python
from dataclasses import dataclass
from pydantic import BaseModel
from pydantic_ai import Agent, RunContext

@dataclass
class ResearchContext:
    api_key: str
    deep_mode: bool

class FactReport(BaseModel):
    statement: str
    verified: bool
    source_citation: str

class SynthesisReport(BaseModel):
    executive_summary: str
    verified_facts: list[FactReport]

# Specialist Sub-Agent
verifier_agent = Agent[ResearchContext, FactReport](
    model='openai:gpt-4o-mini',
    result_type=FactReport,
    system_prompt="Fact-check individual technical claims against primary specifications."
)

# Root Orchestrator Agent
director_agent = Agent[ResearchContext, SynthesisReport](
    model='anthropic:claude-3-7-sonnet-20250219',
    result_type=SynthesisReport,
    system_prompt="Analyze claims and delegate individual verification to the verifier tool."
)

@director_agent.tool
async def verify_claim(ctx: RunContext[ResearchContext], claim: str) -> FactReport:
    """Delegates verification of a specific claim to the specialized verifier agent."""
    sub_result = await verifier_agent.run(claim, deps=ctx.deps)
    return sub_result.data

async def conduct_synthesis(claim_text: str, context: ResearchContext) -> SynthesisReport:
    result = await director_agent.run(claim_text, deps=context)
    return result.data
```

#### 6. Observability & OpenTelemetry Instrumentation with Pydantic Logfire
Instrument agents with zero boilerplate for token tracking, tool latency, and structured traces:
```python
import logfire
from pydantic_ai import Agent

# 1. Initialize Logfire with automatic OpenTelemetry export
logfire.configure(service_name="secops-pydantic-agent", send_to_logfire=True)
logfire.instrument_pydantic_ai()

# 2. Agent operations are automatically traced with token counts & tool timings
monitor_agent = Agent(
    model='anthropic:claude-3-7-sonnet-20250219',
    system_prompt="Autonomous database optimization auditor."
)

@monitor_agent.tool_plain
def calculate_index_efficiency(table_name: str, scan_count: int) -> float:
    with logfire.span("evaluate_index_metrics", table=table_name):
        return round(1.0 - (1.0 / (scan_count + 1)), 4)
```

---

<a name="bahasa-indonesia"></a>
## Bahasa Indonesia

### Integrasi Orkestrasi
- **Bahasa Python & Runtime**: `python-programming-expert`, `structured-output-contracts`
- **Framework Agen & Swarm**: `multi-agent-orchestration`, `ai-llm-integration-expert`, `frontier-ai-models-expert`
- **Protokol MCP & Tools**: `mcp-server-architect`, `parallel-tool-orchestrator`
- **Persistensi & Database**: `database-orm-expert`, `vector-db-rag-expert`
- **Evaluasi & Pengujian**: `autonomous-tdd-debugger`, `property-mutation-testing-expert`, `anti-slop`
- **Siklus Hidup & Tata Kelola**: `zero-to-prod-orchestrator`, `session-memory-manager`

### Deskripsi
Panduan produksi untuk membangun agen AI kelas perusahaan menggunakan **Pydantic AI** (dari pembuat library Pydantic). Tidak seperti library agen yang tidak bertipe statis atau mudah mengalami galat runtime, Pydantic AI menyediakan sistem tipe statis yang ketat (`Agent[DepsType, ReturnType]`), *dependency injection* bawaan kelas satu (`RunContext[Deps]`), validasi parameter tool otomatis melalui skema Pydantic v2, fleksibilitas pergantian model (*model-agnostic*), dan hasil output terstruktur yang terjamin validitasnya.

**Sinergi Swarm:** Di dalam **Backend & APIs Swarm**, skill ini bertindak sebagai Insinyur Agen AI Python Utama. Bertanggung jawab atas eksekusi logika bisnis kritis, orkestrasi pipeline data, dan query database SQL dengan keamanan tipe kompilasi pada Fase 4.

### Kondisi Pemicu
- Membangun agen otonom Python yang menuntut keamanan tipe statis dan validasi skema data ketat.
- Menerapkan injeksi dependensi (koneksi database, klien HTTP, session user) ke dalam tool agen tanpa variabel global.
- Mengekstrak data terstruktur yang dijamin valid dari model penalaran tanpa kegagalan parsing JSON.
- Menjalankan unit test dan evaluasi deterministik pada agen menggunakan model tiruan (`TestModel`).

---

### Implementasi Pola Kunci (Python 3.13+)

#### 1. Agen Type-Safe dengan Injeksi Dependensi Database
```python
from dataclasses import dataclass
import asyncpg
from pydantic import BaseModel, Field
from pydantic_ai import Agent, RunContext

@dataclass
class DependensiDatabase:
    pool: asyncpg.Pool
    tenant_id: str

class LaporanAnomali(BaseModel):
    user_id: str
    skor_risiko: float = Field(ge=0.0, le=1.0)
    peristiwa_anomali: list[str]
    tindakan_disarankan: str

# Agen dengan tipe statis ketat: Agent[TipeDependensi, TipeHasil]
agen_keamanan = Agent[DependensiDatabase, LaporanAnomali](
    model='google-gla:gemini-2.5-flash',
    result_type=LaporanAnomali,
    system_prompt=(
        "Anda adalah auditor keamanan SecOps otomatis. Analisis log aktivitas "
        "dan hasilkan evaluasi anomali terstruktur."
    ),
)

@agen_keamanan.system_prompt
async def tambahkan_konteks_tenant(ctx: RunContext[DependensiDatabase]) -> str:
    return f"Tenant ID Aktif: {ctx.deps.tenant_id}. Hanya audit catatan milik tenant ini."

@agen_keamanan.tool
async def query_log_audit(ctx: RunContext[DependensiDatabase], user_id: str, batas: int = 50) -> list[dict]:
    """Mengambil riwayat autentikasi pengguna dari database audit."""
    async with ctx.deps.pool.acquire() as conn:
        baris = await conn.fetch(
            "SELECT event_time, ip_address, action, status FROM audit_logs "
            "WHERE tenant_id = $1 AND user_id = $2 ORDER BY event_time DESC LIMIT $3",
            ctx.deps.tenant_id, user_id, batas
        )
        return [dict(b) for b in baris]

# Eksekusi agen secara aman:
async def jalankan_audit(pool: asyncpg.Pool, tenant_id: str, target_user: str) -> LaporanAnomali:
    deps = DependensiDatabase(pool=pool, tenant_id=tenant_id)
    hasil = await agen_keamanan.run(f"Audit aktivitas user {target_user}", deps=deps)
    return hasil.data  # Dijamin merupakan instance tervalidasi dari LaporanAnomali
```

#### 2. Pergantian Model Dinamis & Fallback SLM Lokal (Ollama)
Pydantic AI memungkinkan pergantian tanpa friksi antara model cloud frontier dan model open-weights lokal:
```python
import os
from pydantic_ai.models.anthropic import AnthropicModel
from pydantic_ai.models.ollama import OllamaModel

def ambil_model_agen():
    if os.getenv("ENV") == "production":
        return AnthropicModel('claude-3-7-sonnet-20250219')
    else:
        # Pengembangan lokal zero-cost menggunakan Ollama
        return OllamaModel(model_name='qwen2.5-coder:7b')
```

#### 3. Pengujian Unit Deterministik Menggunakan `TestModel`
Tulis pengujian unit yang memvalidasi pemanggilan tool dan parsing output terstruktur tanpa biaya API live:
```python
import pytest
from pydantic_ai.models.test import TestModel

@pytest.mark.asyncio
async def test_eksekusi_tool_agen():
    model_tes = TestModel(call_tools=['query_log_audit'])
    with agen_keamanan.override(model=model_tes):
        deps = DependensiDatabase(pool=mock_pool, tenant_id="tenant_123")
        hasil = await agen_keamanan.run("Audit user 456", deps=deps)
        assert hasil.data is not None
```

#### 4. Validasi Output Terstruktur Real-Time (`run_stream()`)
Stream model Pydantic dengan validasi level-properti saat token diterima secara bertahap:
```python
from pydantic import BaseModel, Field
from pydantic_ai import Agent

class TriaseInsiden(BaseModel):
    tingkat_keparahan: str = Field(description="Rendah, Sedang, Tinggi, atau Kritis")
    komponen_terdampak: list[str] = Field(default_factory=list)
    tindakan_segera: list[str] = Field(default_factory=list)
    hipotesis_akar_masalah: str

agen_triase = Agent[None, TriaseInsiden](
    model='google-gla:gemini-2.5-flash',
    result_type=TriaseInsiden,
    system_prompt="Anda adalah responder insiden keandalan infrastruktur real-time."
)

async def stream_triase_insiden(log_insiden: str):
    async with agen_triase.run_stream(f"Triase insiden: {log_insiden}") as respons:
        async for triase_parsial in respons.stream_structured():
            print(f"[Streaming Validasi Parsial] Keparahan: {triase_parsial.tingkat_keparahan}, Tindakan: {len(triase_parsial.tindakan_segera)}")
        
        hasil_akhir = await respons.get_data()
        return hasil_akhir
```

#### 5. Delegasi & Handoff Multi-Agen Berbasis `RunContext`
Panggil sub-agen sebagai tool terspesialisasi dengan isolasi konteks dependensi:
```python
from dataclasses import dataclass
from pydantic import BaseModel
from pydantic_ai import Agent, RunContext

@dataclass
class KonteksRiset:
    kunci_api: str
    mode_mendalam: bool

class LaporanFakta(BaseModel):
    pernyataan: str
    terverifikasi: bool
    sitasi_sumber: str

class LaporanSintesis(BaseModel):
    ringkasan_eksekutif: str
    fakta_terverifikasi: list[LaporanFakta]

# Sub-Agen Spesialis Verifikasi
agen_verifikator = Agent[KonteksRiset, LaporanFakta](
    model='openai:gpt-4o-mini',
    result_type=LaporanFakta,
    system_prompt="Verifikasi kebenaran klaim teknis berdasarkan dokumen spesifikasi primer."
)

# Agen Utama / Direktur Sintesis
agen_direktur = Agent[KonteksRiset, LaporanSintesis](
    model='anthropic:claude-3-7-sonnet-20250219',
    result_type=LaporanSintesis,
    system_prompt="Analisis laporan dan delegasikan verifikasi klaim ke tool verifikator."
)

@agen_direktur.tool
async def verifikasi_klaim(ctx: RunContext[KonteksRiset], klaim: str) -> LaporanFakta:
    """Mendelegasikan verifikasi klaim tertentu ke sub-agen spesialis."""
    sub_hasil = await agen_verifikator.run(klaim, deps=ctx.deps)
    return sub_hasil.data

async def jalankan_sintesis(teks_klaim: str, konteks: KonteksRiset) -> LaporanSintesis:
    hasil = await agen_direktur.run(teks_klaim, deps=konteks)
    return hasil.data
```

#### 6. Observabilitas & Tracing OpenTelemetry dengan Pydantic Logfire
Instrumentasi performa agen, pelacakan konsumsi token, dan latensi tool secara otomatis:
```python
import logfire
from pydantic_ai import Agent

# 1. Konfigurasi Logfire dengan ekspor OpenTelemetry otomatis
logfire.configure(service_name="secops-pydantic-agent", send_to_logfire=True)
logfire.instrument_pydantic_ai()

# 2. Operasi agen terlacak secara otomatis dalam dasbor telemetri
agen_pemantau = Agent(
    model='anthropic:claude-3-7-sonnet-20250219',
    system_prompt="Auditor pengoptimalan database otonom."
)

@agen_pemantau.tool_plain
def hitung_efisiensi_indeks(nama_tabel: str, jumlah_scan: int) -> float:
    with logfire.span("evaluasi_metrik_indeks", tabel=nama_tabel):
        return round(1.0 - (1.0 / (jumlah_scan + 1)), 4)
```