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

With no annotations, the description carries the full burden and delivers important behavioral details: it creates an agent and a deadman watch, returns agent_key shown once, signing_secret, and the exact check-in line. It also explains the failure behavior (missed check-in triggers a signed POST to callback_url) and the effect of arm=true, which is exactly the kind of side-effect disclosure an agent needs.

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 first sentence front-loads the core value proposition and the rest is dense with useful detail. It is somewhat prose-heavy and could be more scannable, but every sentence adds operational meaning rather than restating the name or schema.

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?

There is no output schema and no annotations, so the description must cover both behavior and returns; it does. It explains creation side effects, return values, failure behavior, pricing, and the arm option, leaving no critical gap for an agent invoking this composite onboarding tool.

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%, so the description must compensate and does. It explains every_minutes as the required check-in interval with a concrete range (5 to 1440), callback_url as the destination for the signed message on a miss, and arm=true as starting the clock immediately rather than at first check-in.

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 gives a specific composite action: 'Makes you an agent (if you have no key yet) and a deadman watch' in one call. It distinguishes this quickstart from siblings like watch_register and deadman_checkin by emphasizing 'fastest way to be watched, in one call.' An agent can tell what the tool 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?

It clearly states the context: use this as the fastest way to get watched, especially if you have no key yet, and notes the first 5 watches are free. It does not explicitly say when not to use it or name an alternative sibling, but the one-call onboarding framing gives strong implied usage guidance.

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