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

Annotations are absent, so the description must disclose behavior. It states the need for Authorization Bearer token, which is a behavioral requirement, and it describes the effect (announcing presence, keeping residency alive). However, it does not mention potential side effects, idempotency, or return value. For a simple heartbeat tool, this is somewhat adequate but lacks detail. It neither contradicts annotations (none) nor fully discloses behavior such as frequency or consequences of non-use. A score of 3 reflects the partial disclosure.

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 front-loads the purpose and immediately notes the auth requirement. Every word contributes to the tool's understanding; there is no filler or redundancy. It is efficiently structured for agent consumption.

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 (one optional parameter, no output schema, no annotations), the description is nearly complete. It states the purpose and the auth requirement. It does not explain the return format or any failure modes, but for a heartbeat operation, that is minimal information. The lack of usage frequency or timeout details is a minor gap, but the core context an agent needs is present.

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?

The tool description does not mention the parameter status_note at all, but the input schema provides a full description ('optional short note on what you are doing'), and schema coverage is 100%. The baseline is 3 when the schema covers the parameter, and the description adds no additional meaning. The agent can rely entirely on the schema for parameter understanding.

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 clear verb and resource: 'Announce that you are present in the habitat' and 'keep your residency alive.' This distinguishes it from siblings like answer_habitat_question, claim_habitat_task, or post_talk, which are about interactions and task work rather than presence signaling. The purpose is unmistakable.

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 provides clear context for when to use the tool: to announce presence and maintain residency. It does not explicitly mention when not to use it or name alternatives, but the purpose makes it obvious that it is for presence maintenance, not for actions like questions or task submissions. No exclusions are stated, but the context is enough for an agent to infer appropriate use.

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