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

With no annotations providing behavioral hints, the description must carry the transparency burden. It discloses that the tool validates required fields and that the new spell is owned by the calling user, which are useful facts. However, it does not mention any side effects, error handling, idempotency, or auth requirements, leaving significant behavioral gaps for an unannotated create operation.

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 two sentences with no redundancy. It front-loads the primary purpose and then adds crucial information about validation and ownership. Every sentence earns its place, and the structure is clean and efficient.

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 create operation with no schema parameters and no annotations, the description covers validation and ownership but leaves gaps. It does not explain the passthrough schema mechanism, error behavior, or how to structure the request. The output schema exists, so return values are documented, but the missing details about parameter passing and failure modes make it incomplete for confident invocation.

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 is empty, so the description's mention of sending ruleset-specific fields (level, casting time, components, etc.) via a passthrough schema adds essential meaning beyond the schema. It compensates for the schema's lack of parameters, though it doesn't list exact parameter names or structures, hence not a full 5.

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 verb 'Create' and the resource 'user-authored spell or power,' which is specific and distinguishes it from other Vault creation tools. The mention of 'user-authored' adds a differentiating nuance, making the purpose unambiguous.

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 some usage context by noting that Vault validates ruleset-specific required fields (level, casting time, components, etc.) and instructs to send them via the passthrough schema. However, it does not explicitly state when to use this tool versus alternatives like vault_create_item or vault_create_rule, nor does it mention exclusions, leaving the selection criteria partially implied.

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