Get Vault Stats

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

Annotations already declare readOnly, idempotent, and non-openWorld, so safety is covered. The description adds genuinely new behavioral context beyond them: reads flow through the mtime cache, so repeated calls are cheap — a performance trait an agent can plan around. It also implicitly discloses the return shape by listing the metrics, which matters since there is no output schema.

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: what it returns, when to use it, and the cost profile. The key content (the metric list) is front-loaded and no sentence is filler.

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 one optional parameter, rich read-only annotations, and no output schema, the description does exactly the extra work needed by enumerating the returned fields and noting cache behavior. 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 coverage is 100% and the single 'folder' parameter is fully documented in the schema, including the omit-for-whole-vault semantics. The description adds nothing on top of that, so the baseline 3 applies.

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 ('Return a quick health snapshot of the vault') and then enumerates the exact metrics returned, so the tool is unmistakable. It never names a sibling to contrast against, which keeps it out of 5 territory, but the metric list does the disambiguating work implicitly.

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 real usage context ('useful for dashboards and is-this-vault-healthy checks'), which tells the agent when this is the right call. It offers no explicit exclusions or alternatives among siblings like read_base or query_base, so it stops short of full when-not guidance.

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