Scaling an Agentic Coding SDK: What Concurrency Actually Costs

This article examines the transition from sequential to concurrent execution in an AI-assisted dependency vulnerability fixer that uses the GitHub Copilot SDK. It details the challenges of running multiple coding agents simultaneously, including workspace isolation, resource limits, rate limiting, telemetry, durable job ownership, and safe retries. The author emphasizes that agent sessions are workloads, not simple HTTP requests, and discusses three key decisions: isolation, concurrency bounds, and persistence. It provides practical insights for developers scaling agent-based systems, highlighting that concurrency costs include operational complexity and the need for robust infrastructure.