Stateful Agentic Engineering Copilots with Letta: Core Memory, Shared State, Semantic Retrieval, Custom Tools, Streaming, and Portable Agent Workflows

This is the available feed excerpt, which may be shortened or in the publisher’s original language.

In this tutorial, we build a stateful engineering copilot with Letta that demonstrates how agentic memory extends beyond conventional prompt-based conversations. We begin by creating inspectable core memory blocks that the agent can autonomously update, then expose those blocks for programmatic state synchronization and shared access across multiple agents. We further extend the architecture with archival vector memory for semantic retrieval, a custom server-side tool for deterministic risk estimation, streaming for observing agent execution, server-side message history for persistent conversations, and .af export for portability. Together, these components demonstrate a practical memory architecture in which persistent state, retrieval, tools, multi-agent collaboration, and execution traces work as an integrated agentic system. Copy CodeCopiedUse a different Browserimport subprocess, sys subprocess.run([sys.executable, "-m", "pip", "install", "-q", "-U", "letta-client"], check=True) import os, json, time, textwrap from getpass import getpass from letta_client import Letta def flex(*attempts, label=""): err = None for fn in attempts: try: return fn() except Exception as e: err = e raise RuntimeError(f"All call variants failed for {label or 'call'}: {err}") from err API_KEY = os.environ.get("LETTA_API_KEY") or getpass("Letta API key (platform.letta.com/api-keys): ") BASE_URL = os.environ.get("LETTA_BASE_URL", "").strip() client = flex( lambda: Letta(base_url=BASE_URL, api_key=API_KEY) if BASE_URL else Letta(api_key=API_KEY), lambda: Letta(base_url=BASE_URL, token=API_KEY) if BASE_URL else Letta(token=API_KEY), label="client init", ) def hr(title): print("\n" + "=" * 92 + f"\n {title}\n" + "=" * 92) def as_text(content): if isinstance(content, str): return content if isinstance(content, list): return "".join(getattr(p, "text", "") or "" for p in content) return str(content or "") def