Fleet summary

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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real scope information beyond the annotations: the counts span both the local host and every worker, clarifying that this is a fleet-wide roll-up rather than a single-host view.

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 sentence that leads with the aggregate framing and then itemizes the metrics. No filler, no restatement of the title, nothing to trim.

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?

With an output schema present, the description needn't explain return values, and zero parameters remove the main source of ambiguity. It covers scope and metric names well; the only gap is routing guidance against the many sibling listing tools.

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 takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The schema has additionalProperties=false and no properties, consistent with the no-argument framing.

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?

States a specific verb ('Aggregate') and resource ('fleet state') and enumerates exactly what is counted: workers online/offline and containers running/total. That aggregation framing distinguishes it from list_workers or get_health_scores, which return per-entity detail.

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 word 'Aggregate' plus the scope 'across the local host and every worker' implies this is the roll-up view rather than a per-worker listing, but it never names a sibling or says when to reach for this instead of list_workers or get_health_scores. Usage is inferred, not stated.

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