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

With no annotations provided, the description carries the full behavioral burden and does so strongly. It warns that zero folders is not an empty library, tells the agent to inspect coverage.empty_reason before concluding emptiness, and explains that updated_at means row-last-touched rather than content-changed, including the bulk-maintenance caveat. This is genuinely useful behavioral disclosure beyond the name and schema.

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?

The main purpose is front-loaded in the first sentence, and each subsequent note earns its place by preventing misinterpretation or wasted operator calls. The REQUIRED/Optional/EXAMPLE block is compact and immediately actionable.

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?

The description is remarkably complete for a simple listing tool: it covers parameter semantics, returned field creative_count, the empty-library pitfall, and updated_at interpretation. The only minor gap is that it does not describe the overall response envelope or whether pagination exists, but for this tool's complexity the description 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?

Schema description coverage is 0%, but the description fully compensates by explaining parent_id as 'str — UUID of parent folder' and by stating that omitting it returns top-level folders. For a single optional parameter, this is complete and unambiguous.

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 opens with 'List creative folders for the authenticated tenant', which names a specific verb, resource, and scope. It also distinguishes itself from the sibling creatives_list by clarifying that root creatives_list returns files with folder_id=null, so an agent can tell the tools apart.

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 clearly states that parent_id is optional and that omitting it means top-level folders, and gives concrete guidance about interpreting zero folders versus an empty library. It does not explicitly say 'use this instead of alternatives', but it makes the relationship to root creatives_list explicit, which gives practical routing context.

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