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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds material context beyond that: it is a background job, it costs credits, and it emits a project id consumed by wait_for_video_project. Only failure/retry and rate-limit behavior are left unstated.

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?

Two sentences, no filler, with the core action stated first and the operational consequences (credits, async job, follow-up tool) second. Every clause carries information an agent needs.

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 7 params including nested objects, an output schema, and full annotations, the description covers the main operational concerns: cost, async lifecycle, and the companion wait tool. The remaining gap is sibling disambiguation against restyle_video and replace_character_in_video, which matters given how many near-identical video tools exist.

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 high (86%), so the schema already documents model tier defaults, resolution constraints, and end_seconds duration limits per model. The description only echoes the required inputs at a high level and adds no meaning about start_seconds, model selection tradeoffs, or the assets path format.

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 and resource ('Edits the appearance or content of a supplied video segment using a text prompt'), which is far more informative than the title 'Edit video'. However, it never distinguishes this tool from close siblings like restyle_video, replace_character_in_video, or translate_video, whose scopes overlap with 'appearance or content'.

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?

The second sentence ('Use with a source video, the requested changes and the clip end time') restates the required inputs rather than saying when to reach for this tool instead of a sibling. The one genuine routing hint is that it 'returns a project id for wait_for_video_project', which is a useful workflow step but not a use-case exclusion.

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