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

Annotations already establish readOnly/non-destructive/non-open-world, and the description adds genuinely new behavior: rendering depends on the host client (card in ChatGPT and Claude), the cost is free, and clients without card support fall back to a short-lived link. That client-dependent output behavior is not derivable from the schema or annotations, though nothing is said about failure when no ready version exists.

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 short sentences, front-loaded with the action, then cost, then the client fallback. Every clause carries information an agent would not otherwise have; nothing is repeated from the annotations or schema.

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 display tool with fully documented parameters and no output schema, the definition covers what the agent needs: what is shown, which version is picked, cost, and what the reply looks like on hosts lacking cards. The remaining gap is error behavior when no finished version is ready.

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 100%, so the baseline is 3, but the description earns above baseline by explaining the semantic default: omitting `versao` selects the latest ready version. That resolves the ambiguity the schema's bare "Version number (optional)" leaves open; projeto, episodio, and language are left entirely to the schema.

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?

"Plays a finished episode video inside the chat" names a concrete verb and resource, and the parenthetical scopes it to a finished/ready version rendered as a visual card. It stops short of naming a sibling (e.g. studio_baixar for download, studio_ver_episodio for episode data), so the agent must infer the distinction rather than being routed explicitly.

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 implies the use case (user wants to see the finished video in-chat) and notes the default of latest ready version, but gives no when-not guidance or named alternatives for downloading or inspecting an episode instead. Usage is inferred from the phrasing rather than spelled out.

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