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

Annotations already flag destructiveHint=true, readOnlyHint=false, and idempotentHint=false, and the description reinforces the destructive replace semantics with the append:true escape hatch. It also discloses that sha256 is the only way to attach a video, a non-obvious constraint. Missing detail on auth or rate limits, so not a full 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?

Three tight sentences: purpose first, entry mechanism second, replace/append caveat last. Every sentence carries load and nothing is padding.

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 destructive, non-idempotent mutation with no output schema, the description covers what gets replaced, how entries are ordered and sourced, and the append escape hatch. The max-20 limit lives in the schema, so nothing critical is missing, but it does not discuss failure modes or result reporting.

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 100%, so the baseline is 3, but the description adds genuine meaning: it explains the three byte-naming strategies (capture/vfs_path/sha256), that capture takes the capture tool's arguments, and that video entries require sha256. This goes beyond restating 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 names a specific verb (Set) and resource (the world's media gallery / screenshots and video trailer shown on its page), and specifies the ordering and entry model. It is clearly distinguishable from siblings like set_world_cover or edit_world_metadata.

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 explains the key behavioral choice an agent faces — that the call replaces the uploaded gallery, so append:true is needed to keep existing entries — which is real when-to-use guidance. It does not explicitly route to or away from named sibling tools, keeping it short of a 5.

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