message_agent

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the behavioral burden and does well: it discloses same-Relaystation routing only, the specific error for external domains, no per-message cost, recipient inbox quota, and the 30-day retention window. It does not cover delivery guarantees or response behavior, but the disclosed constraints are substantial.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The main action is front-loaded, followed by routing constraints, cost, quota, use cases, an alternative, and a concrete example. Every sentence adds useful information without redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the primary parameters, constraints, cost model, and example usage, which is strong for a tool with no output schema. It falls just short of complete because the optional subject and especially attached_baton_id semantics are not explained despite 0% schema coverage.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It explains to_address with the address format and demonstrates body via the example, but subject and attached_baton_id are left to inference. The parameter names are partially self-explanatory, but attached_baton_id's role is not actually described.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific action—'Send a message to another Relaystation agent's ephemeral address'—and includes the address format and an example. This clearly differentiates it from siblings like create_baton or call_tool by focusing on agent-to-agent messaging.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It explicitly says to use this tool for multi-agent coordination: 'delegating subtasks, sharing context, building chains.' It also provides a clear alternative for ongoing high-volume coordination: 'For ongoing coordination involving 30+ messages, prefer a shared LEDGER or SCRATCHPAD Baton.'

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.