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

Annotations already declare read-only, idempotent, non-destructive behavior, so the description does not need to re-state safety. It adds useful behavioral context by specifying that the response contains official fields plus provenance and verify links, helping the agent anticipate the result despite no output schema.

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 sentences with no filler. The core fetch behavior and identifier format are front-loaded, and the routing guidance to the sibling tool comes in a compact second sentence.

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 single-parameter read-only tool, the description covers what it returns, how to identify the record, and when to choose the sibling tool instead. Annotations handle safety characteristics, and there is no output schema requirement being neglected.

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 schema already fully documents the sole parameter with an example, including coverage of 100%. The description echoes registryId as the lookup key but adds little semantic meaning beyond what the schema provides, so the baseline score of 3 is appropriate.

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 states a specific verb and resource ('Fetch one official Hong Kong registry record by registryId') and names the distinctive output ('official fields plus provenance and verify links'). It also differentiates from get_merged_profile by mentioning what this tool does not cover.

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?

It explicitly instructs to prefer get_merged_profile when claim status, enrichment, or recommendedUse citation hints are needed, which tells the agent when not to use this tool and what alternative to select.

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