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

Annotations already declare readOnlyHint=false, idempotentHint=false and destructiveHint=false, so the safety profile is covered. The description adds genuine context beyond that: the required permission (backups.operate) and the fact that the check is re-executed and produces a fresh status. It does not say what the check mutates on the vault, whether a failed check is an error or a reported status, or how fast/reliable the probe is, so it is useful but incomplete.

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?

Three short sentences with zero filler: purpose first, then the triggering condition, then the permission requirement. Nothing is redundant and the most decision-relevant information is front-loaded.

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 action tool with no output schema, the description covers what it does, when to run it, the permission needed, and that it returns the new status. It omits the possible status values and whether the check mutates stored vault state, which would fully close the loop, but nothing an agent needs to invoke it correctly is missing.

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?

Only one parameter exists and schema description coverage is 100% (vault_id, sourced from list_backup_vaults), so the schema already does the work. The description adds no syntax, format, or lookup detail beyond the schema, which matches the baseline of 3 for high-coverage single-parameter tools.

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 names a specific verb (re-run the platform's credential check) against a specific resource (a backup vault's bucket) and states that it reports the resulting status. The 're-run ... new status' phrasing implicitly separates it from pure readers like get_backup_vault, but it never names an alternative sibling outright, so it sits just below the top tier.

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?

'Use this after rotating or fixing the vault's access keys' gives a concrete triggering condition, and 'Requires backups.operate' states the permission prerequisite. There is no explicit when-not guidance or named alternative (e.g. get_backup_vault for cached status), so it stops short of a 5.

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