Pydantic AI + MemorySync
One capability gives every run recalled context and success-only turn persistence — no history pollution.
Overview
Install pydantic-ai-memorysync and add MemorySyncCapability(user_id=...) to Agent(capabilities=[...]): recall injects through the framework’s instructions channel — never a conversation part, so message-history replay can never stack stale memory blocks — and turns persist in after_run, which fires only on success, so a failed run leaves no half-remembered turn. Identity resolves from your deps for multi-user servers. Five structured tools plus a typed search tool returning validated Pydantic models. The only memory integration built on pydantic-ai v2’s capability system.
Setup status and requirements
- Supported version
- pydantic-ai-memorysync 1.0.0 (PyPI)
- Last setup review
- 2026-08-23
- Permissions
- A MemorySync API key with read and write scopes; the delete tool needs delete permission.
- Limits
- Requires pydantic-ai (or pydantic-ai-slim) >=2 <3 (Python 3.10+). Python only — TypeScript agents use the Vercel AI SDK or Mastra integrations.
Capabilities
- Built on the pydantic-ai v2 capability system (competitors pin <2)
- Recall rides the instructions channel — replay-safe by construction
- One recall per run, replayed across multi-request tool-calling runs
- Success-only persistence: failed runs leave no half-turns
- Identity from your deps: user_id_resolver or ctx.deps.user_id
- Typed search results: list[MemoryResult] Pydantic models
- Five never-raise agent tools with a read-only mode
Quick Start
from pydantic_ai import Agentfrom pydantic_ai_memorysync import MemorySyncCapabilityagent = Agent("openai:gpt-5",instructions="You are a helpful assistant.",capabilities=[MemorySyncCapability(user_id="customer-7")],)result = await agent.run("What should I cook tonight?")
Use Cases
Pydantic AI agents that remember users across runs and deploys
Multi-user servers resolving identity from typed deps
Structured pipelines consuming typed memory search results
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