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

Beyond the readOnlyHint annotation, the description adds valuable behavioral context: it is fast ('Fast'), scope-limited ('bounded loc_id list'), reports geometry vintage, and emphasizes it is a preflight (no side effects). It also discloses the 'shape-only' limitation, which is not evident from annotations alone.

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 three sentences, front-loads the core purpose, and every sentence contributes unique value: what it does, what it reports, its usage context, and cost/limitations. No wasted words or repetitive content.

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?

Despite the lack of an output schema, the description clearly explains the tool's return concept ('reports whether each exact identity has reusable geometry and its geometry vintage'), which is sufficient for an agent to understand the expected output. It also provides performance, cost, and usage context, making it a complete picture for a preflight 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?

The input schema already provides 100% coverage with clear descriptions for all four parameters, so the description adds minimal parameter-specific meaning. The phrase 'bounded loc_id list' is slightly informative but the schema already mentions the deployment-configurable cap, so the description does not significantly elevate understanding.

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 clearly states a specific action (preflight check) on a specific resource (loc_id geometry), and distinguishes itself from sibling tools by explicitly noting it does not resolve points or explain identity relationships. The phrase 'shape-only preflight' encapsulates the tool's unique role.

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?

Explicit guidance is provided: 'Use before get_geometry or an export.' The description also clarifies what the tool does NOT do (resolve points, explain relationships), which helps agents avoid misusing it for those purposes. 'No payment required' adds a relevant usage consideration.

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