index_fonts

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

Annotations are minimal (readOnlyHint=false, destructiveHint=false), so the description carries the disclosure burden. It clearly reveals the outFile side effect, the exact catalog contents, and that omitting outFile yields facets only. It does not address overwrite behavior or any access/rate considerations, but those are minor for this 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 tight sentences with no filler. The facet behavior is front-loaded, and the outFile behavior and rationale follow immediately without redundancy.

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?

Complete for a tool with one optional parameter and no output schema. It explains the facet output, the optional file output, the contained fields, and the relationship to search_fonts. An agent has enough information to call it correctly.

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 fully documents outFile, so the baseline is 3. The description adds value beyond the schema by specifying the catalog's field list and the local grep/jq use case, making the parameter's purpose and benefit concrete.

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 action ('Catalog facets') and a concrete resource (the font catalog), enumerating the facet dimensions (category, subset, license, type, variable/static). It also explicitly contrasts itself with search_fonts, so an agent can distinguish the two tools.

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?

Gives explicit usage guidance: use this tool to get facet counts, and use outFile when you want the full 2000+ catalog locally for grep/jq. It also names the alternative (search_fonts) and explains why you would avoid paginating it.

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