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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered without the description. The description adds that the estimate is "blended" and conditioned on a retry rate, which is modestly useful context, but it says nothing about how the retry rate affects the result or what the returned figure represents.

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 with no filler, front-loaded with the verb and the output quantity, with the conditioning input stated at the end. Nothing can be trimmed without losing 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?

With 4 parameters, 25% schema coverage, and no output schema, the description should carry more weight than it does. It never states the units for retryRatePct or avgCostPerTask, nor what the returned estimate looks like (single figure, breakdown, currency), leaving real ambiguity for a numeric-estimation tool.

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 25% – modelId is documented, but runsPerMonth, avgCostPerTask, and retryRatePct have no descriptions. The description names "retry rate" but does not resolve the critical unit ambiguity (percent vs fraction) or clarify whether avgCostPerTask is per attempt or per shipped task.

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 ("Estimate") and a precise resource ("blended cost per shipped task for a month of agent runs"), which distinguishes it in substance from siblings like cursor_auto_cost_estimate and swarm_run_cost_estimate. It does not name those siblings or explain how the estimates differ, so it stops short of a 5.

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?

There is no when-to-use guidance, no prerequisites, and no mention of when another estimator (cursor_auto_cost_estimate, swarm_run_cost_estimate) would be the better choice. The only signal is the implied context of "agent runs," which the agent must infer.

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