Why Running Agent Loops Can Cost You Hundreds of Thousands of Won in Token Fees
Passing your entire codebase to an agent is a surefire way to trigger a cost explosion. Developers who fail to manage context exhaust their token limits in just a single day, wasting 42 percent more in unnecessary costs. The solution is not complicated. Create an .agentignore file in your project root, and list node_modules, build, and dist in it. This makes the agent ignore these folders, reducing input token volume and speeding up response times by 2.5 times.
The real trouble starts when an agent gets stuck repeating failing commands. A survey of 100 junior engineers showed that money lost from unmonitored infinite loops averaged 150,000 won per person monthly. Standard error output must be captured in real-time. Use a Python script that cuts off the process if an error occurs three times in a row. Run the agent as a subprocess and parse stderr. If the same error code is logged three times, immediately execute sys.exit(1). This completely blocks scenarios where your wallet gets drained.
There are times when an agent modifies code and insists that everything is done. Without clear verification criteria, the probability of misinterpreting malfunctioning code as normal is 30 percent. Parse the unit test result JSON file and proceed to the next step only when the success rate is 100 percent. Read test_results.json and check the passed field. If the condition is not met, fail the build and feed the error log into the next prompt. It is the only way to prevent deployment disasters.
When terminal session management is messy, multi-agent work falls apart. Without proper session management, the context loss rate skyrockets up to 65 percent. Launch independent sessions using tmux, and stream the standard output of each session into a unique log directory in real-time. Even if a session dies, recover it by loading the checkpoint saved in the local sqlite3 DB. This is a realistic architecture for running agent pipelines without session conflicts.