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

The description adds valuable behavior beyond the annotations: the operation is asynchronous, returns a job id, persists a job, and must be polled at a specific cadence. It does not discuss job expiry, failure modes, or permission requirements, but with annotations already declaring non-read-only, non-idempotent, open-world behavior, the added workflow context is substantive.

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 description is front-loaded with the core action and is only three sentences long. Every sentence adds useful information: the action, the return value and polling workflow, and the sibling-tool preference.

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?

There is no output schema, so the description appropriately explains that a job id is returned and describes the polling and retrieval steps needed afterward. Combined with the rich input schema and annotations, it gives an agent enough context to invoke and follow up correctly.

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 100%, so all five parameters, including enums, are already documented in the schema. The description adds only contextual wording such as “URL you already host,” without parameter-specific details beyond the schema, making the baseline 3 appropriate.

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 description states a specific verb and resource: start a persisted subtitle job from a URL. It clearly distinguishes this from upload-based flows by saying no upload is needed and by naming lunara_upload_video as the alternative.

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 usage guidance: prefer this over lunara_upload_video whenever media is reachable by URL. It also describes the follow-up workflow, polling lunara_get_job every 15–30 seconds and then calling lunara_get_srt.

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