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

Annotations already mark the tool as read-only and non-destructive. The description adds useful behavioral context beyond that by defining exactly what 'health' means: status histogram, missing supplements, drifted approved cards, and generation run summary. This helps the agent predict what the tool reports without contradicting the annotations.

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 entire description is one dense sentence that front-loads the core purpose and then lists the key metrics in a dash-separated sequence. Every phrase contributes meaning, and there is no filler or repetition of the tool name or title.

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 parameterless read-only tool with an output schema, the description covers all essential context: what corpus it applies to, the aggregate nature of the data, and the specific metrics an agent can expect. No critical usage or behavior details are 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?

The tool has zero parameters, so the baseline is 4. There is no parameter detail needed, and the description correctly focuses on what the tool returns rather than input semantics.

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 ('Get'), a clear resource ('Key-Facts supplement corpus'), and enumerates four concrete outputs (status histogram, missing supplements, drifted cards, generation run summary). It distinguishes the tool as an aggregate health overview from sibling tools like list_drifted, but it does not explicitly name a sibling or state what this tool is not.

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 implies this is the right choice for high-level corpus health summaries rather than item-level listing or search, but it never explicitly states when to use this tool versus siblings such as supplement_status or list_drifted. An agent must infer the boundary from the word 'aggregate' rather than being told.

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