Coding Agents for Software Engineers

Architecture, Context, and Efficient Usage 1️⃣ What Is a Coding Agent? A coding agent is not just an LLM . It is a system: IDE / CLI ↓ Agent Runtime ↓ Context Builder ↓ LLM Inference ↓ Tool Execution (fs, git, tests, shell) ↓ Loop The model is only the reasoning engine. The runtime handles orchestration. 2️⃣ General Architecture of a Coding Agent A production-grade coding agent includes: 1. Indexing Layer Repo scanning Symbol extraction Dependency graph Optional embeddings 2. Context Builder Select relevant files Inject instructions Add plan/scratchpad Add recent edits 3. LLM Inference Layer Tokenized prompt Context window constraints Streaming output 4. Tool Layer File read/write Test execution Git diff/patch Lint/build commands 5. Loop Controller Plan Execute Validate Iterate The model does not “see the repo.” The agent chooses what to send. 3️⃣ What Is the Context Window? The context window is: The maximum number of tokens the model can attend to in a single inference call. It inclu