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

Annotations already declare readOnly=false, destructive=false, and non-idempotent, and the description is consistent with them. It adds real behavioral context beyond the annotations: partial updates leave untouched fields alone, folder is tri-state, clearFolder overrides folder, and system is deep-merged rather than replaced. That materially aids safe invocation, though it doesn't discuss auth, side effects on linked documents, or return behavior.

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, scoping/clarifying the trickiest parameters first (folder tri-state, then system merge). Every clause carries information 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?

For a 6-parameter partial-update mutation with no output schema, the description covers the non-obvious semantics (tri-state, merge, clearFolder) that an agent needs to call it correctly. It is nearly complete, with only minor gaps around affected linked data or permission requirements.

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 100%, so the schema already documents every parameter's meaning, including tri-state folder, deep-merge system, and the clearFolder null-workaround. The description largely restates those same semantics (tri-state, deep-merge, clearFolder precedence) rather than adding new meaning, so the baseline of 3 applies.

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 (Update) and resource (world item) and enumerates the updatable facets: name, image, folder, system data. An agent can distinguish it from world-item-create/delete/get by name alone, but the description never explicitly contrasts itself with those siblings, keeping it short of a 5.

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 tri-state rules ('omit = unchanged', 'null/clearFolder = move to root') and the deep-merge instruction effectively tell the agent how to call the tool in each case, which is useful conditional guidance. However, there is no explicit when-to-use/when-not or named alternative (e.g., vs world-item-create), so usage context is only implied.

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