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

The description goes beyond the annotations by explaining that the rule is owned by the calling user and defaults to 'house rule' unless the caller is an admin. It also discloses that the vault validates the payload and that missing required fields produce a vault error, adding concrete behavioral context.

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?

The description is concise and front-loaded with the primary purpose, followed by key behavioral facts in two sentences. Every sentence adds value without repetition or 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?

Given that an output schema exists and the tool has no formal input parameters, the description covers essential aspects: creation, ownership, validation, and error handling. It does not enumerate the required payload fields, but that information is likely available elsewhere (e.g., in API docs or output 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?

The input schema has zero parameters, so the baseline is 4. The description mentions a 'payload' that the vault validates, hinting that the actual rule content is passed in the request body, which is useful context even though the schema is empty. It does not add parameter-level detail beyond that.

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 description clearly states the action 'Create a new user-authored rule' and lists all supported rule categories (class, race, background, etc.), which immediately distinguishes it from sibling tools like vault_create_item and vault_create_spell. The explicit enumeration leaves no ambiguity about the resource type.

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 provides clear context: this is for creating user-authored rules, not for creating items or spells, and the admin nuance clarifies ownership behavior. However, it does not explicitly name alternatives or state when not to use the tool, though the sibling list makes alternatives obvious.

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