send_to_subagent

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

The annotation destructiveHint=true already signals potential destructive outcomes, and the description does not contradict it. The description adds minimal behavioral context beyond the annotation, not detailing what happens when the message is sent or whether it interrupts the subagent.

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 description is a single concise sentence that fully conveys the tool's core purpose without unnecessary filler. It is appropriately front-loaded and easy to parse.

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?

Given the tool's simplicity, the rich schema, and the presence of an output schema, the description is mostly complete. It could include a bit more about side effects or expected outcomes, but for a low-complexity tool, this is sufficient.

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 100%, so parameters are fully documented in the schema. The description itself adds no parameter details, but since the schema covers all three parameters, the baseline score is appropriate.

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 clearly states the action ('send a follow-up message') and target ('running subagent'), using a specific verb and resource. It differentiates from siblings like launch_subagent and stop_subagent, though it could more explicitly name alternatives.

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?

The phrase 'to a running subagent' implies this tool is used after launch and before stopping, providing clear context. However, it does not explicitly state when not to use it or mention any alternatives, so guidance is implied rather than direct.

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