Multi-Agent Cost Guide

The basic budget formula

A useful first estimate is: agents times average tokens per turn times turns per agent, plus coordination overhead, divided by one million, times blended model price. The formula is simple because the architecture question is simple: how many model calls does the split create, and what useful signal do those calls buy?

The hard part is choosing honest inputs. A coordinator may call the model to plan, delegate, inspect worker results, ask follow-up questions, synthesize, and judge. Workers may search, read, retry, and compress. A judge or reviewer may add another pass. If those calls are invisible in the prototype budget, production cost will look like a failure rather than a design choice.

Use the multi-agent cost estimator to run the formula with your own agent count, turns, tokens, model price, and baseline assumptions.

Coordination overhead is not waste by default

Some overhead is the price of quality. Delegation tells workers what to do. Artifact summaries preserve decisions. Judge passes catch weak evidence. Traces make failures diagnosable. Those tokens are useful when they replace confusion with verifiable state.

The problem is unbounded overhead. A system that lets workers ask vague follow-ups, duplicate searches, debate without a judge rubric, or retry tool calls without a stop rule will spend tokens without improving confidence. Coordination should have budgets, not just prompts.

The baseline multiplier matters more than the raw bill

A ten-dollar multi-agent research run may be cheap if it replaces hours of analyst work and finds better sources. A ten-cent support answer may be expensive if a single agent could answer in one call. Compare the architecture to a credible baseline, not to zero.

The baseline should be the simplest system you would actually ship: one agent, clear instructions, the necessary tools, retrieval where useful, and an eval set. If the multi-agent design costs four times more, it should produce better coverage, more reliable citations, safer policy separation, or measurable quality gains.

Cost controls that preserve quality

Useful controls do not merely cut tokens. They prevent low-value work. Give each worker a maximum turn count, source budget, and stop condition. Ask for structured artifacts rather than long transcripts. Let the coordinator reject weak artifacts instead of expanding the task indefinitely. Add human gates for high-cost or high-risk branches.

The cost decision is ultimately the same as the architecture decision: did the split create more verified signal than overhead? If the answer is unknown, prototype against a single-agent baseline and measure before adding agents.