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 genuinely new behavioral context not in the annotations: it is public and requires no API key, which affects how an agent calls it. It stops short of describing result shape or whether 'settings' is exhaustive.

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 short sentences, zero filler, with the resource and payload front-loaded and the access note trailing. Nothing redundant.

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?

A simple read-only listing tool with one optional param and no output schema; the description adequately covers what the tool delivers and how it is accessed. The only material gap is the unexplained 'mode' filter, which for a low-complexity tool keeps it short of full completeness.

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% for the single optional 'mode' parameter. The description says nothing about it, and the enum values 'i2v'/'t2v' are unexplained abbreviations (image-to-video vs text-to-video) whose filtering effect and default-when-omitted behavior are left entirely unaddressed.

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?

States a specific verb and resource ('List Stivio video models') plus the payload contents (supported settings, per-second credit rates). It clearly reads as a discovery/catalog tool distinct from generate_video or estimate_video_cost, though it never names a sibling to contrast itself with.

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?

'Public; no key needed' gives context on accessibility, and listing models implies a discovery-before-generation use case, but the description never says when to call this versus estimate_video_cost or generate_video. Usage must be inferred.

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