tenki_report_sandbox_activity

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

Annotations already signal non-readonly, non-idempotent behavior. The description adds valuable context beyond that by explaining the keep-alive heartbeat mechanism and the consequence of preventing idle reaping. There is no contradiction with the annotations.

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?

A single front-loaded sentence with no filler: action, resource, purpose, and consequence are all present. Every clause 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 one-parameter heartbeat tool with no output schema and annotations covering the side-effect profile, the description gives the agent enough to call it correctly. No critical information is missing.

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% and already explains session_id as 'The sandbox/session ID to mark as active.' The tool description does not add extra parameter semantics, so the baseline 3 applies.

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 names a specific verb and resource ('Report client-side activity on a sandbox') and states the operational effect ('reset its idle timer and keep it from being reaped as idle'). This clearly differentiates it from lifecycle/read/list siblings.

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 gives a clear context for use: report client-side activity to reset the idle timer and prevent idle reaping. It does not explicitly name alternatives like tenki_extend_sandbox or state when not to use it, so it falls 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.