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

Annotations only signal readOnlyHint=false, so the description carries the burden of explaining state changes. It does so by disclosing that 'success' resets the deadline and that the message is kept as the run log. It stops short of covering broader side effects like authentication or persistence details, but the key mutation behavior is transparent.

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 concise sentences front-load the status semantics and the key side effect (deadline reset), with no filler, repetition, or unnecessary detail. Every sentence earns its place.

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?

For a simple check-in tool, the description covers purpose, statuses, the message parameter, and the deadline-reset behavior. The main gap is that it does not describe what the tool returns or what the agent should expect as a response, which is more notable because there is no output schema.

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 already 100%, but the description adds value by defining what each status means (success resets deadline, start begins a run, fail reports failure) and clarifying that the message becomes the run log. It does not add anything about monitor_id, but the schema already documents that parameter clearly.

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 uses a specific verb ('Report on') and resource ('heartbeat monitor'), then enumerates the three statuses and their meanings. It is clearly distinct from sibling tools like get_monitor or pause_monitor, which perform different lifecycle 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 gives explicit lifecycle timing for each status: 'success' after a completed run, 'start' when a run begins, 'fail' when it failed. It also explains the deadline reset, which helps an agent choose the correct status. However, it does not explicitly name alternative tools or state when not to use this tool, so it falls just short of a 5.

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