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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so 'Read-only' is largely redundant. The description does add behavioural context beyond the annotations: it discloses that a single call spans three resource types and that it doubles as a diagnostic check for catalog ad buildability. It stops short of describing pagination, result volume, or what happens when no catalogs exist.

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 compact sentences, front-loaded with the resource list, then the downstream use case, then the alternative. No filler and no repetition of the 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 four-optional-parameter read-only listing tool with full schema coverage and no output schema, the description supplies purpose, downstream dependency and alternative. The only gap is that it never indicates the shape or granularity of what comes back across the three resource types, which would matter when only one catalog is selected.

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 100%, so the schema already documents folder, account, catalog and language. The description's phrase 'or of one catalog' hints at the catalog filter but adds no syntax or precedence detail beyond what the schema states. Baseline 3 is appropriate since the schema carries the parameter burden.

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?

Names a specific verb (List) and three concrete resources (product catalogs, product sets, dynamic templates) scoped to the ad account's Snapchat organisation. The parenthetical '(or of one catalog)' clarifies the scoping behaviour, and the sibling snapchat_product_performance is explicitly excluded, so an agent can distinguish it from adjacent catalog/performance 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 when-to-use cases: retrieving catalog_id, product_set_id and dynamic_template_id for snapchat_create_catalog_campaign, and diagnosing why catalog ads cannot be built. It also names the alternative for per-product performance, so both the 'use this when' and 'use something else when' conditions are covered.

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