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

Beyond the annotations, it reveals the merge behavior ('only supplied fields... merges them'), the optimistic concurrency requirement, and the failure mode (OUT_OF_SYNC, nothing written). This is exactly the behavioral context that helps an agent predict consequences and is consistent with the readOnlyHint=false and destructiveHint=false annotations.

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?

Every sentence is load-bearing and the core action is front-loaded. The description packs access control, merge semantics, and concurrency behavior into four short sentences with no filler.

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?

The definition covers access, update mechanics, required optimistic-lock field, stale rejection, and no-write-on-failure. The only minor gap is that the world id itself is not specified as a literal input key, and updatable world fields are left to inference, but these are recoverable from the tool name and the referenced get_world read.

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?

With an empty input schema, the description is the only source of parameter meaning, and it clearly names the required baseUpdatedAt field and its value source. It does not enumerate other updatable fields or the exact key for the world id, but the merge semantics plus openWorldHint make the rest inferable from the world document returned by get_world.

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 opening clause 'PUT updates to one world by id' names the verb, the resource, and the identifying scope in one compact sentence. This clearly differentiates it from the sibling update tools for adventure, adventure_page, and world_page without needing to compare schemas.

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 states the authorization precondition ('must have edit access') and gives a precise usage requirement: copy updatedAt from a fresh imagine_get_world read and supply it as baseUpdatedAt. It does not explicitly list alternatives or when-not-to-use, but the context is clear enough that an agent can decide to call this tool for world updates.

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