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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds real value beyond that: the authorization caveat that catalog presence does not grant generation authority, plus the pagination model ('stable ID cursor') and its 50/100 bounds. It stops short of describing ordering or what a stable ID cursor looks like in practice.

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 short sentences, front-loaded with the resource and scope, then the semantic caveat, then pagination mechanics. No filler and nothing repeated for its own sake.

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, return values needn't be spelled out, and the two optional params are covered. What remains thin is ordering guarantees and whether the tenant's configured set can be narrowed; for a simple read-only catalog list this is close to 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?

Schema description coverage is 0%, so the description must carry this load, and it does explain both params: limit defaults to 50 with a 100 max, and cursor is a stable-ID-based cursor rather than an offset. It does not say what the cursor string is obtained from (presumably the previous response's next-cursor), which is a minor gap.

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?

Uses a specific verb+resource ('Read configured languages available to this tenant') that unambiguously distinguishes it from the other catalogs_* siblings (fonts, models, music, transitions, voices). The scope qualifier 'available to this tenant' further pins down what set is returned.

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?

'Catalog entries do not grant generation authority' hints at how to interpret results but is a caveat, not usage guidance. Nothing states when to call this versus catalogs_models/catalogs_voices, nor any prerequisite or exclusion. Usage is only implied by the resource name.

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