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

Annotations already cover the read-only, idempotent, non-destructive profile, and the description goes well beyond them: a hard 30-day media expiry, newest-first ordering, the per-item shape (prompt, model, status, result URL, billing), and the gems vs unlimited billing distinction. These are operational constraints the agent cannot get from the structured fields.

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 tightly packed sentences with the core purpose and time window front-loaded. It is dense with return-field and pricing detail, but nothing is filler; a minor trim of the billing clause would not change meaning.

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?

No output schema exists, so the description carries the burden of explaining what each record contains, and it does so along with expiry and cross-tool references. The only shortfall is that pagination shape (next_cursor) is left entirely to the schema.

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 limit, cursor, status, media_type, and architecture are already documented. The description's mentions of `source` and `request_id` refer to returned fields rather than inputs, and it adds no filter syntax or usage nuance beyond the schema, so the baseline 3 applies.

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 plus the exact scope and ordering: 'List the account's generations from the last 30 days, newest first.' It then names the sources (Mage app, API, MCP server, auto-creation) and the sibling that holds a different corpus, so an agent can distinguish it from search_creations immediately.

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?

Explicitly routes the agent: this tool is for the 30-day history, while the user's permanently saved creations live in search_creations. It also names get_request and cancel_request as the consumers of the returned request_id, giving a clear follow-up path.

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