Patterns
Parallelization Pattern in Python: Fan-Out LLM Calls (2026)
Run independent LLM calls at the same time in Python with asyncio.gather, cap them with a Semaphore, and survive 429 rate limits with backoff. Runnable code.
6 min read112
Author
Ren Okabe
Ren builds agent infrastructure and writes copy-paste tutorials for engineers shipping LLM tool-use systems.
Patterns
Orchestrator-Workers Pattern in Python: A Claude Tutorial (2026)
Build the orchestrator-workers agent pattern in Python with Claude: a planner that decides subtasks at runtime, parallel workers, and a synthesizer. Runnable code, July 2026.
6 min read119
Patterns
Agentic Workflow Routing: Build an LLM Router in Python (2026)
A code-first routing tutorial: build a runnable LLM router in Python with the Claude API, add a deterministic fallback, and route by difficulty to cut cost.
5 min read91
AI agents
LangGraph Checkpointer: Persist and Resume Agent State (2026)
Make a LangGraph agent durable with a checkpointer: attach SqliteSaver in one line, crash the graph on purpose, and resume from disk without re-running the Claude call.
8 min read199
Patterns
Prompt Chaining in Python: A Runnable Claude Tutorial (2026)
A code-first prompt chaining tutorial: build a gated Python pipeline with the Claude API, add pure-Python and LLM gates, and fail fast before wasting tokens.
7 min read106
MCP
How to Add an MCP Server to Claude Desktop (2026)
The exact claude_desktop_config.json setup to connect a local MCP server to Claude Desktop, verify it with the MCP Inspector, and fix a server that will not show up.
8 min read171
Evaluation
LLM as a Judge: Score AI Agent Outputs with Claude (2026)
A minimal, framework-free LLM-as-a-judge harness in Python on Claude: rubric design, pointwise and pairwise scoring, and fixes for position, verbosity, and self-preference bias.
7 min read109
Testing
AI Agent Testing: A Runnable Pytest and LLM-Judge Harness (2026)
You cannot unit-test an agent like a pure function. Build a two-layer pytest harness: deterministic tool-call assertions plus an LLM-as-judge grader, a frozen eval dataset, and a CI gate. Runnable Python, no eval framework required.
6 min read129
Patterns
Agentic Workflow Patterns in Python (2026)
Five reusable agentic workflow patterns, built from scratch in Python with runnable code and a start-simple rule.
5 min read119
From scratch
Self-Hosted AI App Builder: Run Your Own (2026)
A hands-on 2026 tutorial: stand up your own self-hosted, open-source AI app builder from the ai-app-builder-open repo, with one API key and code you fully own.
10 min read140
AI agents
Remote MCP Server Tutorial (2026): Serve Tools over Streamable HTTP
A runnable 2026 tutorial for turning a local MCP server into a remote one over Streamable HTTP. Serve tools with FastMCP, test the endpoint with curl and MCP Inspector, validate the Origin header, add a bearer token, then connect Claude. Covers the Mcp-Session-Id requirement and the DNS-rebinding gotcha the docs warn about but most walkthroughs skip.
9 min read199
AI agents
LangGraph Human-in-the-Loop (2026): Pause an Agent for Approval with interrupt()
A runnable LangGraph human-in-the-loop tutorial for 2026: pause an agent mid-run with interrupt(), review the proposed action, then approve, edit, or reject it with Command(resume=...). Includes the checkpointer requirement and the re-run-from-the-top gotcha that breaks most tutorials.
5 min read128