connection_status

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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, but the description adds the operational meaning behind those hints: the call performs no network I/O, no browser interaction, no token refresh, and incurs no query cost. The warning that 'a saved token cannot prove Google still accepts it' is precisely the caveat an agent needs to avoid over-reading a success result — value that no annotation or schema field carries.

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 constraining scope statement front-loaded before the alternative-tool pointer. No filler, no restatement of the name, and the caveat arrives in the position where an agent will actually read it.

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?

An output schema exists, so return-value explanation is correctly omitted, and the behavioral envelope is fully covered. The only real omission is guidance on the 'account' parameter and, secondarily, how this differs from health_check. For a zero-required-parameter, read-only status tool, that is a small residual gap.

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 tool has one parameter, 'account', with 0% schema description coverage and no default explanation beyond null. The description never mentions the parameter at all, so it adds no meaning about what an account value does or what happens when it is omitted. With low coverage the description was expected to compensate, and it does not.

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 concrete capability — reporting local setup status — and immediately bounds it ('no network, browser, token refresh or query costs'), which lets an agent distinguish it from every sibling that touches BigQuery. The verb-object pairing is somewhat oblique ('Report local setup') rather than a clean 'checks X', but the scope statement makes intent unambiguous.

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 names the alternative explicitly ('Use list_datasets for an explicit metadata access test') and gives the reason to switch — this call never claims live access. It stops short of enumerating when this tool is the preferred choice versus health_check, which is the closest sibling, so routing between those two is left implicit.

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