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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds behavioral value by listing exactly which metrics are returned (storage totals, plan limits, collection sizes, daily query counts), which is useful since there is no output schema. It does not clarify scope (e.g., account vs workspace) or freshness, keeping it from a 5.

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?

Two sentences, front-loaded with the tool's output content and then the usage trigger. Every clause adds distinct information and there is no 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?

For a zero-parameter read-only tool with no output schema, the description supplies the key return categories and the reason to call it. It is nearly complete, though it could note whether the stats are scoped to the account, workspace, or agent.

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 of 4 applies per the scoring guidelines. There are no parameter semantics to add beyond the empty schema.

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 ('Get your memory usage statistics') and enumerates the concrete metrics returned (total facts stored, plan limits, collection sizes, daily query counts). It clearly identifies the tool's scope, but does not explicitly differentiate itself from the sibling 'index_stats', which could be confused as another stats tool.

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 states the trigger condition: 'Call this to check how much storage you have used and how close you are to your plan limits.' That is clear when-to-use guidance, though it offers no when-not-to-use or named alternatives.

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