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

Annotations already signal a non-read-only operation, but the description adds meaningful behavior: ownership on the calling user, validation of ruleset-specific fields, and the passthrough mechanism. This goes beyond the hints without contradicting them.

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 sentences with the purpose first and no redundant filler; every sentence adds either scope, field semantics, or ownership behavior.

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 zero-argument tool with an output schema, the description covers purpose, validation, and side-effect ownership, so the agent can form a correct mental model. The only notable ambiguity is the reference to a 'passthrough schema' that is not represented in the exposed input schema.

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 and zero parameters, the baseline is 4 and the description carries the load by naming concrete validated fields (damage, properties, equip slots, weight) and pointing to the passthrough schema. It adds meaning that the empty schema cannot, though it leaves the exact passthrough format unspecified.

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?

Opens with a specific verb and resource ('Create a new user-authored item') and enumerates concrete item types, so an agent can tell it apart from sibling creators like vault_create_character, vault_create_spell, and vault_create_rule. The extra detail about vault-validated fields further pins down what this tool does.

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 gives clear context: use this tool to create new user-authored items, and send ruleset-specific fields through the passthrough schema. It does not explicitly name alternatives or exclusion conditions, but the item-specific scope is strong enough to guide selection among the many vault siblings.

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