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

Annotations already declare readOnlyHint=true, so the 'Read-only' sentence is largely redundant, but the description adds real value beyond annotations: 'Bucket credentials are never returned' discloses a privacy/security behavior, and the enablement precondition explains when the tool exists at all.

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 tight sentences, front-loaded with the resource and its definition. Slight redundancy in restating 'Read-only' that the readOnlyHint annotation already carries.

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, but the description enumerates the returned fields and discloses the credential-exclusion behavior, which is what an agent needs. Minor gap: no mention of ordering or pagination for the list.

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?

There are zero parameters, so the baseline is 4. The description compensates by naming the result fields (provider, bucket, verification status, last-verified time), which adds useful semantic context even though no input parameters exist.

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 (List) and resource (backup vaults), and goes further by defining what a vault is ('S3-compatible buckets cluster backups and migration data move through') plus the fields returned. This clearly separates it from get_backup_vault and list_backup_vault_imports.

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?

The gating condition 'Only offered when backups are enabled for the organisation' is a useful precondition, but the description does not contrast this list tool with the sibling single-vault get_backup_vault or list_backup_vault_imports. Usage is implied rather than routed.

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