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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false and openWorldHint=false. The description adds one genuinely useful behavioral fact beyond annotations: no credit spend and no media generation. But it omits what happens on duplicate titles, what is returned, or whether the world is immediately visible to other tools like get_world.

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 compact sentences, front-loaded with the action and field list, followed by the key constraint. No filler text, though the field enumeration is somewhat redundant with the schema.

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 7-parameter mutation tool with no output schema and 0% schema coverage, the description is only marginally adequate. It flags no-credit-spend, which is valuable, but leaves field semantics, arrays, and the 'owned' concept unexplained.

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% across 7 parameters, so the description must compensate. It names six of the seven fields but provides no semantics: it does not explain that 'theme' aliases 'description', that lists are capped at 50 items, or what a 'video production cue' should contain. The schema lists property names only; the description largely repeats them.

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 owned world') and enumerates the content fields it accepts (title, description, genre, visual style, lore, production cues). It distinguishes itself from siblings like create_world_asset and update_world, though 'owned' is never explained.

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 clause 'No media generation or credit spend' implies when this is the right tool (setup before asset generation) but does not explicitly name alternatives such as create_generation_request or estimate_generation_cost. Usage is implied rather than stated.

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