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

Annotations only declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), so the description carries useful extra weight: it discloses PATCH-style partial-update semantics and, importantly, that empty strings/arrays clear optional fields, plus that existing media is untouched. No auth or rate-limit details, but the mutation semantics are well covered.

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 short, front-loaded sentences with no filler. Each sentence earns its place: purpose, update semantics, and the media boundary.

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?

There is no output schema and annotations cover only safety, so the description is the main source of behavioral context. It addresses clearing and omission semantics but omits the field inventory and any permission/ownership requirements, which matters for an 8-parameter mutation tool with 13% schema coverage.

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 only 13% (only world_id is documented), so the description must compensate for seven undocumented parameters. It conveys the string-vs-array clearing behavior for optional fields but never enumerates the updatable fields (genre, theme, title, description, visualStyle, importantLore, videoProductionCues), leaving their meaning and constraints to the schema names alone.

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?

Names a specific verb and resource ('Update an owned world's descriptive fields') and scopes it away from non-descriptive content with 'Does not rewrite existing media', which implicitly separates it from update_world_asset. It does not explicitly name a sibling, so it falls just short of full sibling differentiation.

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 description implies partial-update usage through 'Omitted fields remain unchanged', which tells the agent how to call it, but there is no explicit when-to-use / when-not-to-use guidance and no mention of alternatives such as create_world, update_world_asset, or delete_world.

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