printer_usage_summary

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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds value beyond that by disclosing the failure mode ('when the figure cannot be had (offline, signed out), the count comes back with why, and where the prices are') and by noting the tool is free on every plan, which an agent needs to know before surfacing cost implications.

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 core question is front-loaded in the first sentence and the operational note follows logically. Some phrasing is roundabout ('what they add to your bill on your plan, at your plan's prices', 'so ask it on the computer your printers are attached to'), which costs a little density but does not obscure meaning.

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 zero-parameter, read-only tool with full annotation coverage, the description covers purpose, where to run it, failure behavior, and what comes back (a count plus a reason and pricing location). With no output schema, a slightly more explicit statement of the return shape would have closed the remaining gap.

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; the baseline applies. Nothing in the text misleads about inputs either.

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: it counts printers registered to this Kiln and reports their cost impact on the plan. That is clearly distinguishable from most siblings, but it never names or contrasts with close alternatives such as usage_summary or printer_stats, which an agent could easily confuse with it.

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 real context on where to call it from ('ask it on the computer your printers are attached to'), which is a genuine usage constraint. However, it offers no explicit when-not guidance and no routing to alternatives like usage_summary or fleet_status when the agent wants billing data instead of a printer count.

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