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

With no annotations, the description carries the full behavioral burden, yet it discloses nothing about delivery semantics, what happens if target_agent_id is unknown, whether relay is synchronous, or error behavior. A routing/mutation tool with zero annotation coverage needs far more.

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 single phrase is front-loaded and free of waste, but it is under-specified rather than genuinely concise; the brevity comes at the cost of any actionable detail.

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?

For a 3-parameter tool with a nested object payload, no annotations, and no output schema, the description is inadequate — it omits routing behavior, delivery/failure semantics, and message structure expectations.

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 only 33% — only ttl is documented ('Hop limit for relay'), while target_agent_id and the nested message object are undocumented. The description adds no parameter meaning to compensate, leaving the nested message structure entirely opaque.

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?

States a clear verb+resource ('Relay message') and a scope ('through swarm'), and is distinguishable from the receive-oriented sibling swarm_inbox. However, it does not explicitly name or contrast with any sibling, so it falls short of full differentiation.

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?

There is no when-to-use guidance, no preconditions, and no mention of alternatives such as swarm_inbox for the reverse direction or agents_plan for coordination. The agent must infer usage from the name alone.

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