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

Annotations only say read-only/non-destructive; the description adds the materially important behavior that the call blocks up to wait_seconds, that the job continues to completion regardless of polling, and what the response fields mean. That is exactly the context an agent needs to avoid a polling loop.

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?

Front-loaded with purpose and trigger condition, then return shape, then the non-obvious 'runs to completion whether or not you poll' note. Slight overlap between 'waits for it rather than returning immediately, so one call is usually enough' and the final sentence, but no sentence is wasted.

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, and the description fully compensates by enumerating the return fields, the three status values, and where outputs and errors appear. For a two-parameter blocking read tool, nothing an agent needs in order to call it correctly 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 coverage is 100%, so the baseline is 3, but the description adds the intent behind wait_seconds ('how long you are willing to hold') and frames it as a tradeoff rather than a raw number. job_id is described only indirectly via the 'returned from the starting tool' framing, which the schema already covers.

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 (fetch the outcome) and resource (a media job) plus concrete examples of what such jobs produce (article GIF, frame grab). Crucially it pins the tool to the exact trigger condition — 'the tool that started it returned { job_id, status: "processing" }' — which separates it from generator siblings like generate_media or add_article_media.

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?

Gives clear when-to-use context (only after an inline-incomplete start) and tells the agent one call usually suffices, so it should not be looped. It stops short of naming the specific alternative for other job types (e.g. get_script_job for scripts), so the sibling routing is implied rather than explicit.

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