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

The readOnlyHint annotation already establishes this as a safe read operation. The description adds meaningful context by specifying what the estimate covers and clarifying that it is not a canonical release bundle, which helps the agent understand the tool's non-destructive estimation 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?

The description is two sentences, immediately states the tool's purpose, and wastes no words. It is front-loaded with the key action and outcome, then a short clarifying distinction.

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?

Given the complex schema and no output schema, the description compensates by listing the key return elements (count, availability, bytes, etc.). It does not explicitly state the requirement to provide loc_id, loc_ids, or scope, but the schema's anyOf enforces that, and the description is otherwise complete for an estimate 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 86%, so the schema already handles most parameter meaning. The description does not add significant parameter-level details beyond saying 'selected geometry export,' but the high schema coverage justifies the baseline score.

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 begins with 'Dry-run estimate for a selected geometry export,' using a specific verb and resource. It enumerates the exact output dimensions (loc_id count, shape/vintage availability, bytes, delivery mode, citation requirements, charge units) and explicitly differentiates from a canonical release bundle, making the purpose unmistakable.

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 description clearly frames the tool as an estimator for export artifacts and excludes canonical bundles, implying use before or instead of actual export creation. However, it does not explicitly reference sibling tools like create_geometry_export or state 'use this before creating an export,' so the guidance is clear but not fully explicit.

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