Agent communication is the exchange of information among agents in a software system. It determines which context each agent can access and how agents interact while completing a task. section 4.1 section 4.1.2
Communication is distinct from decision-making and control. Decision-making chooses the next action, control executes it, and communication carries information between agents. section 4.1
Choose a communication pattern according to the context each agent needs:
- Message passing sends only the required messages or objects, reducing noise and context cost; its quality depends on the previous agent's output. section 4.1.2
- A shared message thread gives every agent the previous exchanges and can support recovery, but growing context increases token use and may reduce focus. section 4.1.2
- Tool exchange through MCP provides structured, narrowly scoped communication, but adds the overhead of a tool call for each exchange. section 4.1.2
Competitive analysis
An orchestrator assigns one research agent to each of three companies. Each researcher receives only its company name, rubric, and output schema. A synthesis agent receives the three completed reports, but not the orchestrator's internal planning notes. This boundary avoids unnecessary cost and helps each agent focus on relevant evidence. section 4.1.2
Table 4.3 Flow communication patterns: Pros and cons
| Communication pattern |
Pros |
Cons |
| Message passing |
Simple and effective Limits messages to just what is needed Filters out noise |
Messages are only as good as the previous agent’s output. |
| Shared message thread |
All agents are aware of previous exchanges. Robust; failures in agent execution may be recoverable |
Context window size grows with each agent. Increases token use. Can cause confusion; agents may lose focus and perform other tasks |
| Tool exchange (MCP) |
Limits messages to just what’s needed Communication is structured and well-defined. |
Overhead of making a tool call for each communication |
Compare message passing, shared message threads, and MCP by their benefits and failure modes. section 4.1.2
