configure_cost

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

With no annotations, the description carries the full burden. It does add real behavioral context: the wear formula and the fact that values are snapshotted at print end rather than re-applied retroactively, which matters for correctness. But it is silent on whether the call merges with existing settings or replaces them (all 6 params are optional), and on any permission or persistence behavior.

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?

Two sentences, front-loaded with the action, then a dense enumeration of inputs and the one piece of timing semantics that an agent cannot infer. No 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 6-param, no-annotation, no-output-schema tool with thin schema coverage, the description covers almost all parameters and adds the snapshot-timing rule. The notable remaining hole is update granularity (partial vs full replacement) and the currency parameter's format.

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 only 17%, so the description must compensate, and it largely does: it explains electricity_per_kwh, printing_watts, machine_wear_per_hour (including the price/life-hours + upkeep formula), per_print, and filament_price_per_kg keyed by type. Only 'currency' is left unexplained in both places.

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+resource ('Set the cost model') and enumerates the cost inputs it governs. It is distinguishable from estimate_cost and cost_report, which consume rather than set these values, though the description never makes that contrast explicit.

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?

Usage is implied by the enumerated inputs, and the closing sentence gives useful timing context ('costs are computed when a print ends, with the values in force then'). However, it names no alternative and gives no prerequisites or conditions for when a cost model must be configured versus queried.

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