send_message

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

No annotations are present, so the description carries the burden. It discloses that the tool auto-detects executor and auto-queues if busy. However, it lacks details on failure modes, required permissions, or side effects, which would justify a higher score.

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 concise and well-structured with XML tags separating use case, parameters, and example. Every sentence is informative without redundancy. The front-loaded purpose and clear organization earn top marks.

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 moderate complexity and lack of an output schema, the description covers the essential aspects: purpose, parameters with defaults, and an example. It could mention possible return values or error handling, but it is largely sufficient for the task.

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 baseline is 3. The description adds value by explaining that executor is 'Auto-detected from session' and auto_queue means 'Queue if busy,' beyond just repeating the schema. One parameter (variant) is not described in the text, slightly diminishing completeness.

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 explicitly states the verb (send) and resource (message to a coding agent session), making the purpose clear. It distinguishes itself from sibling tools like cancel_queue or get_queue_status, which are different actions.

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 includes a <usecase> that says 'Send follow-up instructions to an active session,' providing context on when to use it. It also mentions auto-queuing behavior. However, it doesn't explicitly state when not to use it or offer alternatives, which would earn a 5.

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