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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds genuine behavioral context beyond that: it is one immediate snapshot and must never be looped, and a status question with an id must never be answered null. It does not describe the returned status values, but the snapshot/no-loop rule is a meaningful non-obvious trait.

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 routing intent is front-loaded and useful, but the text is a run-on packed with quoted example phrases and repeats the '(not a song / voice-over / stitched render)' exclusion twice. It is denser than needed and could be tightened without losing routing information.

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 single-parameter, read-only status tool with no output schema, the description covers routing, exclusions, and the no-loop behavior thoroughly. The one remaining gap is that it never hints at what the returned status looks like, though the absence of an output schema lowers that expectation.

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 0% (the single property is an undescribed string), so the description must carry the burden. It does clarify that placeholder_id accepts either a placeholder id or a var2 link/URL, which meaningfully extends the bare schema type.

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 names a specific verb+resource (status check for a VIDEO clip) and immediately scopes it against siblings by media word, explicitly excluding song, voice-over, and stitched render. An agent can distinguish this from var2_get_image_result or var2_get_dialog_result without opening any 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 triggers (status questions with an id/link), when-NOT (action verbs like 'animate it'/'upscale' route to create/modify tools), and names the exact alternative siblings (var2_check_join_status, var2_get_dialog_result). It even handles the edge case of a null answer and points to the paired create tool.

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