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

Annotations already declare readOnlyHint: true, so the safety profile is covered. The description adds valuable behavioral context by specifying exactly what is returned: current verdict, latest latency, 24h uptime, ordering (worst-first), and the network-wide rollup, which goes beyond the annotation.

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 extremely concise: two sentences that front-load the core purpose ('List monitored hosts') and then add essential output details. Every sentence is informative with no wasted words.

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 list tool with no parameters and no output schema, the description provides comprehensive information about the return value: the fields, ordering, and inclusion of a rollup. It fully explains what the agent can expect, making it complete for its complexity.

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?

The tool has zero parameters, so the schema provides no parameter semantics. The description correctly omits any parameter details. Baseline for 0 parameters is 4, and there is nothing to add.

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 clearly states the tool's purpose: 'List monitored hosts' with a specific verb and resource. It further distinguishes itself from siblings like get_host and get_network_summary by detailing the unique output: verdict, latency, uptime, worst-first ordering, and a network-wide rollup.

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 usage for obtaining a broad overview of all monitored hosts, including metrics and a rollup. It does not explicitly name alternatives or exclusions (e.g., 'for a single host, use get_host'), but the context is clear enough for an agent to select this tool when a comprehensive list is needed.

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