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

Annotations already declare read-only, idempotent, non-destructive, non-open-world, so the safety bar is low. The description adds genuinely useful context beyond that: signed links imply auth-scoped URLs, 'Supported hosts receive players' discloses a host-dependent return shape, and the explicit 'No generation or credit charge' rules out cost concerns.

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?

Three compact sentences with the return payload front-loaded and zero filler. Mild ambiguity in 'finished results beside unfinished edits' and 'selected range files' costs it a point, but nothing 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?

An output schema exists, so return values need not be enumerated, and annotations carry the safety profile; the description still covers cost, output medium, and partial-result behavior. The main gap is the lack of routing against the status/export siblings.

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?

Only one parameter (projectId) and schema description coverage is 100%, so the schema fully documents it; the baseline of 3 applies. The description adds nothing about the id or errors when the project lacks a finished master.

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 and resource: 'Returns current edit status and signed playback links.' The 'finished master or selected range files' framing clarifies scope, but it never distinguishes this preview tool from close siblings like studio_video_status, studio_video_export, or studio_motion_preview, so an agent must infer the boundary.

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?

Usage is only implied by the return-oriented phrasing and the title 'Play the finished video'; there is no explicit when-to-use or when-not, and no sibling is named as the alternative for status checks versus playback.

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