mma_describe_catalog

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

With no annotations, the description carries the full burden. It explains the two behavioral modes based on the category parameter, including live counts and listing facets. It implies read-only nature, but does not detail performance or limits, which is acceptable for a read-only schema description tool.

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 with zero waste. The first sentence states purpose and timing, the second explains behavior and a critical usage rule. Every word earns its place.

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?

Given no output schema and a single optional parameter, the description is largely complete. It explains what the tool returns in both cases and provides a usage rule. It could be slightly more detailed about the output structure (e.g., counts, facets format), but overall it is sufficient.

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 schema already covers the category parameter, but the description adds significant value by explaining how the tool's behavior changes with and without it, listing categories with counts and returning facets/enums. This goes well beyond the schema's brief description.

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 clearly states the tool reads the self-describing facet schema, specifying different behavior with and without a category. It distinguishes itself from sibling tools by emphasizing its role as a precursor to searching or listing, using specific verbs and resource references.

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 explicitly says 'BEFORE searching or listing' and provides a rule 'Only use facet keys + values it returns — never invent them', guiding when and how to use it. However, it does not explicitly mention when not to use it or provide direct alternatives, though the context makes it clear.

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