Estimate the cost of a grid

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

Annotations already declare readOnlyHint and openWorldHint, and the description goes further with genuinely useful behavior: nothing is reserved or charged, and points at sea are removed for shapes (so the estimate can differ from a naive count). It does not describe latency, rate limits, or how the balance figure is derived.

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 compact sentences with the output promise, the run_grid relationship, and the cost profile all front-loaded. No filler, no repetition of the title.

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 9-parameter tool with no output schema, the description does well to enumerate the conceptual return values (point count, credit cost, resulting balance), which removes the need for a return-value schema. However, it leaves all nine parameters undocumented, which is a real gap for a tool this parameterized.

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 0% across 9 parameters, so the schema supplies names and constraints but no meaning. The description only offers 'Same parameters as run_grid' plus a hint about shape/sea points, leaving the agent to infer semantics for radius_km, density, place_id, and the rest from a sibling tool's definition.

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 and resource ('estimate ... what a grid would cost') plus the exact output quantities (points and credits). It also explicitly positions itself relative to run_grid ('before running it'), so an agent can distinguish it from the sibling that actually executes a grid.

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?

Clearly frames the usage window ('before running it') and notes it is free, implying it should be called ahead of run_grid. It stops short of an explicit 'call this first, then call run_grid' instruction or any when-not-to-use guidance, but the context is unambiguous.

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