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

Annotations already declare readOnlyHint=true, so "Read-only" is partly redundant, but the description adds a genuinely useful guarantee not in the annotations: "Bucket credentials are never returned." This tells the agent what sensitive data it will and won't receive.

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 waste: the returned fields lead, the credentials caveat and id-discovery hint follow. Every sentence earns its place.

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?

With a single required parameter, a fully-covered schema, and no output schema, the description closes the gap by enumerating the return payload. Nothing an agent needs to call this 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?

Schema description coverage is 100%, so vault_id is already documented in the schema. The description reinforces provenance by pointing to list_backup_vaults as the source of the id, but adds no format or constraint detail beyond the schema baseline.

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 ("Show one") and resource ("backup vault"), then enumerates the returned fields (provider, endpoint, region, bucket, verification status, error excerpt, timestamps). This clearly distinguishes it from the sibling list_backup_vaults.

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?

Explicitly routes the agent to list_backup_vaults for discovering vault ids, giving clear context for this single-item lookup. No explicit when-not-to-use, but the retrieval-by-id framing makes the intended call site obvious.

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