subagent_send_message

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

No annotations are provided, so the description carries the full burden. It discloses a key behavioral trait: each follow-up creates a new rollback segment. This adds value beyond just stating the purpose. However, other aspects like idempotency, error handling, or permissions are absent.

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?

Two sentences, front-loaded with the purpose, and no unnecessary words. Every sentence earns its place by conveying essential information.

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?

Despite having an output schema, the description omits parameter guidance and usage alternatives. For a tool with 4 parameters and no annotations, the description provides only the rollback context, leaving gaps in understanding how to use each parameter effectively.

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% and the tool has 4 parameters (target, message, items, interrupt). The description fails to explain any of these parameters, only mentioning segment_id which is not a parameter of this tool. The description does not compensate for the missing schema descriptions.

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 tool sends a follow-up message to an existing subagent run. The verb 'send' and resource 'follow-up message' are specific and distinguish it from siblings like spawn, close, rollback, or wait.

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 description explains how to use segment_id with subagent_rollback for undo, but does not provide explicit guidance on when to use this tool versus alternatives. It implies usage for follow-up messages, but lacks when-not scenarios or comparative context.

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