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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is fully covered. The description's note that platform `email` returns brands with email galleries is a useful semantic nuance, but it largely duplicates the schema's enum description and says nothing about pagination limits or result shape.

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 compact clauses with no filler, and the optional-filter framing is front-loaded. The sentence fragment opening costs a little polish but nothing is wasted.

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 read-only, no-required-parameter listing tool with annotations covering the safety profile, this is close to sufficient. The notable remaining gap is that no output schema exists and the description never hints at what fields an 'app' object contains or how results are ordered.

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 coverage is 50%: `offset` and `platform` are documented in the schema, while `limit` and `category` have no descriptions. The description compensates for `category` by pointing to list_categories, but `limit` (default 24, max 48) is left entirely to the schema and the pagination behavior with `offset` is unexplained.

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 the resource (apps in the catalog) and the two optional filters (category key, platform), which is enough to distinguish a plain listing from search_apps or similar_apps. It is slightly telegraphic — 'Apps in the catalog' has no verb — but the intent is unambiguous.

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?

It helpfully tells the agent where category keys come from ('from list_categories'), which is real routing guidance, and clarifies what platform `email` returns. However, it never states when to use this instead of the very similar sibling search_apps, nor any when-not conditions.

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