i ran 11 research agents in parallel for one day. honest accounting, including the two that did nothing

saw the income accounting post here and figured the same honesty is useful for agent workflows, because the parallel-agents posts i see all skip the failure column. the job: sweep a big pile of reddit data for a research project. 11 agents, each with its own written brief, each writing one output file. what it cost: 890 api credits in one day, which turned out to be most of the months quota. i found that out three days later when everything started failing and i spent an hour diagnosing an "outage." what worked: 9 of 11 produced genuinely good files. the whole sweep took about 4 hours instead of the two days it wouldve taken serially. what didnt: 2 agents launched with empty briefs because a temp folder got cleaned between writing the prompt and launching. both exited green. both reported success. i only caught it because the output files didnt exist. an agent with no instructions does not error, it just agreeably does nothing. also the api i was hammering rate limited everyone, including the agents that were fine, so the real concurrency ceiling was the upstream service, not my machine. rules i kept: max 2-3 concurrent, briefs verified non empty before launch, done means show me the file. i moved the orchestration into coldtea-ai after this since it keeps the brief as a file the agent actually reads, but honestly the checks matter more than the tooling. net: parallel was worth it, at about half the parallelism i started with.