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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds that comparison is purely on price and optional monthly cost, but says nothing about return format or how per-model results are structured. With annotations carrying safety, a 3 is fair.

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 front-loaded sentence with no waste; the model-count constraint and optional dimension are stated immediately.

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 7-param read-only tool with 86% schema coverage, the description conveys the essential behavior. The main gap is that with no output schema, it doesn't sketch what a comparison result looks like, but overall it is adequate.

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 coverage is 86%, so the schema itself documents nearly all parameters including presets and token defaults. The description adds only the 2-5 bound and the optionality of workload cost, which is largely redundant with the schema's minItems/maxItems and preset description.

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 (compare) and resources (price, monthly workload cost) with a clear 2-5 model scope. This distinguishes it from single-model siblings like get_model_price, though it doesn't name alternatives explicitly.

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 'optionally' clarifies that a workload cost estimate is conditional on providing workload params, but it doesn't state when to prefer this over estimate_cost or cheapest_models_for. Usage is implied rather than guided.

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