cache_status

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

Annotations already declare readOnlyHint and openWorldHint. The description adds valuable behavioral context: it discloses the cache initialization side effect (though read-only) and the performance implication of the first call taking minutes. This is beyond what annotations convey and helps the agent anticipate behavior.

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 sentences, no waste. The primary purpose is front-loaded, followed by essential guidance and an alternative. Every sentence earns its place, and the structure is easy to scan.

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 an output schema present, the return format is covered. The description explains the side effect (cache init), performance characteristics, and provides an alternative for update checks. For a parameterless tool, this is fully complete.

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 no parameters, so the baseline is 4. The description correctly omits parameter details since none exist, and there is no additional parameter-related meaning needed. The description adds value through behavioral context, not parameter explanation.

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 states a specific verb and resource: it returns cache status and WHO source-document details, and initializes an empty cache. This clearly distinguishes it from siblings like refresh_cache (which refreshes) and check_for_updates (which checks updates without downloading). The purpose is explicit and unambiguous.

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 description provides explicit usage guidance: it warns that the first call may take minutes and suggests pre-warming with a terminal command, and it directs users to check_for_updates as an alternative for checking newer data without downloading. This is a clear when-to-use and when-not-to-use with an alternative.

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