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

Annotations cover the mutation/safety profile (readOnlyHint=false, destructiveHint=false), and the description adds value beyond them: it declares the operation is 'Free,' discloses that missing video durations are probed in the workspace and images default to 3 s, and names the returned identifiers. It does not discuss failure modes or limits on the probing behavior, so it stops short of a 5.

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-loads the purpose and the deliverable, then the parameter guidance, then the workflow — a sensible order with little filler. The sentence enumerating returned fields is somewhat redundant given an output schema exists, keeping it out of the top score.

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 create tool with an output schema, the description supplies everything needed: what it produces, where inputs come from, cost, defaults for duration, and the downstream tool chain with its required prerequisite. Nothing an agent needs to invoke 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 description coverage is 0%, so the description must carry the parameter burden. It does well on the most complex parameter — clips are ordered main-track http(s) URLs, sourced from media_confirm publicUrls, with durationSeconds from `vg probe` and a 3 s image default — but says nothing about aspectRatio (an enum with a default), trimStartSeconds, sourceDurationSeconds, kind, or label.

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 ('Create an editable VidGuy video project') and immediately defines what the artifact is — an editable deliverable with an editorUrl. It is clearly distinguishable from the sibling tools video_project_edit, video_project_review, and video_project_export, which are named in sequence.

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?

Explicitly routes the agent through the lifecycle: create here, then 'build with video_project_edit, check with video_project_review, and export with video_project_export,' and names the upstream prerequisite 'call get_workflow_instructions first.' It also tells the agent where clip URLs come from (media_confirm publicUrls), so the ordering of other calls is unambiguous.

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