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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so the safety profile is covered and the description does not contradict it. The description adds the meaningful detail that passing binId null relocates to the library root, but says nothing about whether the item is removed from its previous bin, batch limits, or failure behaviour for a mutation tool.

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?

A single front-loaded sentence with the key convention in parentheses; nothing is wasted. It is arguably too terse for the mutation it performs, but conciseness itself is not the problem.

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 three-parameter mutation with no output schema and one-third schema coverage, the definition covers the destination semantics but omits return behaviour, cross-project caveats, and what happens to media already in another bin. Adequate to invoke, thin for predicting effects.

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 only 33% (only projectId is described in the schema), so the description carries real weight here, and it does explain the non-obvious nullable required binId convention. However mediaIds (array, minItems 1) and the interplay of projectId with the move target are left entirely to the schema.

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 gives a specific verb ('Move') and resource ('media items') plus the destination ('into a bin'), which is enough to separate it from move_clip, move_track, move_effect and move_projects by resource type. It does not explicitly name those siblings, but the resource noun does the differentiating work.

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?

There is no guidance on when to use this versus move_clip/update_media, no prerequisite or permission context, and no exclusion. The only usage-adjacent information is the null-means-root convention, which is really parameter semantics rather than when-to-use guidance.

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