Vault statistics

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds real behavioral value beyond that: it discloses the diagnostic nature of the output and surfaces the internal search_mode fallback ('fts5' vs 'like'), which is unusual and useful context.

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?

The purpose sentence is front-loaded and efficient. The follow-up enumeration is long but each item earns its place since there is no output schema to describe the return shape; a minor redundancy exists between 'statistics and health information' and the explicit field list.

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 no output schema, the description fully carries the burden of describing the return payload: totals, per-namespace counts, top tags, active-TTL count, db size and path, schema_version, and search_mode with its enum values. An agent knows exactly what it will get back.

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 takes zero parameters, so the baseline is 4. The description correctly implies no inputs are needed; there is nothing further to document.

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 pair ('Get vault statistics and health information') and immediately enumerates the scope of what is returned. It is clearly distinguishable from recall/remember/forget by topic, but it never explicitly contrasts itself with any sibling.

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?

Usage is only implied. The parenthetical '(handy to pick tags consistently)' hints at one diagnostic use case, and the 'health information' framing implies introspection, but there is no explicit when-to-use, when-not, or alternative tool named.

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