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

Annotations already declare readOnlyHint, idempotentHint and closed-world, so safety is covered. The description adds real domain context absent from structured fields — credit costs (5/10 credits), duration limits, account eligibility for the credit-pack-only film product, and that music/subtitles are opt-in. However, it never describes the tool's own behavior, e.g. whether results are static/cached or what a caller gets back.

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 pithy purpose is front-loaded, which is good, but it is followed by one sprawling multi-clause sentence dense with pipeline internals (Seedance 2.5, Nano Banana Pro) that a caller selecting the tool does not need. Several details feel like marketing copy rather than decision-relevant information.

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 no output schema, the description carries the burden of explaining what comes back, and it does convey the substance of the two products and their options. But it never states the response shape (a list of what — IDs, names, descriptors), which is the one thing an agent needs before invoking a listing tool.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline of 4 applies. The schema is empty and fully consistent with a no-argument listing tool.

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 opening clause states a concrete verb and resource ('Lists Kleo's one template... and its two products'), so the agent knows this is a catalogue-enumeration tool. No sibling (kleo_create_video, kleo_storyboard_guide, kleo_account, etc.) overlaps with listing, so differentiation is implicit rather than stated. The rest of the sentence drifts into product details rather than sharpening the purpose.

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?

There is no explicit when-to-use statement, no mention of a prerequisite step preceding kleo_create_video, and no named alternative. The reader can infer it is a discovery step, but nothing tells the agent when to call it versus going straight to creation or the storyboard guide.

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