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

With no annotations, the description carries the full burden and does disclose the non-obvious auth mechanics: the signing_secret is passed as `Authorization: Bearer <signing_secret>` for this call and no agent key is required. It does not say what happens when a check-in is late, whether it is idempotent, or what the response looks like, leaving some gaps for a tool whose whole purpose is timing.

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?

Three short sentences, front-loaded with the purpose and effect before the auth detail. No wasted words and nothing buried.

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?

With no output schema and no annotations, the description covers purpose, auth, and credential provenance, which is the core of calling this correctly. It omits failure/timing behavior and return values, but those are secondary for a check-in call.

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 coverage is 0%, so the description must compensate, and it fully explains signing_secret's origin ('returned at registration') and transport (Bearer header). watch_id is left unexplained, but its role is obvious from the name, so the one genuinely non-obvious parameter is covered.

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 specific verb and resource ('check in on a deadman watch') and the outcome ('keep it from firing'), which clearly separates it from the sibling mutation tools watch_cancel and watch_register. An agent can tell what this does without opening the schema.

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 implies recurring use ('keep it from firing') but never states when to call it versus watch_cancel, watch_get, or watch_register, nor any timing/deadline constraint that matters for a deadman switch. Usage is inferable but not explicit.

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