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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds genuinely new behavioral context: the check never fetches the URL, cannot confirm the test exists or is open, and returns reasons and fixes in both Japanese and English.

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 purpose, scope, and limitations are front-loaded, and each sentence carries information. The bilingual duplication makes it long, but since returning bilingual output is a feature of the tool, the mirroring is defensible rather than wasteful.

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?

No output schema exists, yet the description explains the return content (verdict plus reason and fix, in JP and EN). Combined with the single documented parameter and the stated boundaries, an agent has everything needed to call it correctly and interpret the result.

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?

Single required parameter with 100% schema description coverage, so the schema already carries the meaning and gives an example. The description reinforces the canonical closed-test URL shape, but adds no format constraints beyond what the schema example implies. Baseline 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?

States a specific verb and resource (format-check a Google Play testing opt-in URL without login) and enumerates the three classifications (closed test vs internal test vs store page) it distinguishes. An agent can tell exactly what this tool does and, via the explicit 'format check only' clause, what it does not.

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?

Gives two concrete trigger scenarios (verifying a URL to share with testers; diagnosing why the Play Console tester count didn't increase) plus an explicit exclusion: it does not open the URL and does not verify the test exists or is open. Siblings (get_service_info, how_to_get_testers) are distinct enough that no misrouting is likely.

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