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

Beyond the annotations (write, non-idempotent), it discloses the upload auth mechanism (X-550W-Upload-Ticket header, no OAuth on upload), that an image upload triggers a paid task, retry semantics (8-64 char operationId, same file), and that failed/deleted/expired operations are not recreated. This is rich context an agent could not infer from the annotation block.

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 core action is front-loaded, and each sentence adds operational detail (auth header, paid task, follow-up calls, consent, retry rule). It is dense and longer than typical, but nearly every clause earns its place; only the operationId/retry sentence feels slightly compressed into the flow.

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 and only generic annotations, the description still conveys the full lifecycle: ticket issuance, upload mechanics, the returned uploadUrl/taskId, terminal-status polling, and the video hand-off. Nothing an agent needs to invoke and follow through is missing.

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%, so the description must carry the parameter burden. It explains the mediaType branches and the operationId constraint, but fileSize is never explained, and operationId is referenced yet absent from the schema, leaving some ambiguity. It compensates partially but not fully.

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 first sentence names a specific verb and resource ('Get a short-lived upload ticket') and immediately differentiates the two media branches, routing image uploads to get_image_watermark_task and video uploads to submit_subtitle_task. An agent can distinguish this from every sibling without opening a schema.

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?

It gives explicit when-to-use routing for both media types, states a precondition (obtain user consent for upload and paid processing first), and names the follow-up tool for each branch. The no-separate-image-creation-tool note removes a common wrong turn.

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