agent_online_check

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

Annotations already declare this as a safe read-only operation, so the bar for additional disclosure is lower. The description adds valuable behavioral context beyond annotations: it exposes the `online` field and explains the consequence of `online: false` for send_imessage, namely queuing without dispatch until the Mac is back online.

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 two sentences, front-loaded with the tool's purpose and followed by the operational caveat that affects send_imessage. Every sentence adds clear value with no repetition or filler.

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 no-parameter status check with annotations covering safety, the description is complete enough to call correctly. It explains the key result field (`online`) and the important downstream behavior when the agent is offline.

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?

This tool takes no parameters, so there are no parameter semantics to document. Per the evaluation baseline, a zero-parameter tool receives 4 when the description does not create confusion about inputs.

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 specific verb and resource: checking whether the user's Mac agent is running and able to dispatch iMessages. It also explicitly connects the result to send_imessage, which distinguishes it from sibling tools like get_draft_status or list_drafts.

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 clearly implies when this check matters by explaining that if `online: false`, send_imessage will queue a draft without dispatching it. It does not explicitly say to call this before send_imessage or compare it directly with get_draft_status, but the context is strong and unambiguous.

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