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

With no annotations, the description carries the full burden. It discloses one key behavioral trait: the need for npub for credit billing, implying a paid operation. But it does not mention whether the operation is idempotent, what happens if the person or day already exists, or any side effects beyond creation. The description is too sparse for a mutation tool.

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 only two sentences, front-loaded with the main action and followed by the key requirement. Every word is efficient with no redundancy 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?

The description is brief and does not explain what 'Event+Person+Day' conceptually means or what the output will be (though an output schema exists). The schema fills in parameter details, but the composite nature of the operation and its relationship to other tools (e.g., why not create separately) are not elaborated. It is minimally adequate but leaves gaps.

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 coverage is high (86%), with parameter descriptions already explaining most fields. The tool description adds 'Requires npub for credit billing,' but this duplicates the schema's explanation for npub ('Required... for credit billing'). It does not clarify parameters like date, person, or event_name beyond what the schema provides, so it adds little value.

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 states a clear action: 'Create an Event+Person+Day in one action.' This specifies the verb (Create) and the composite resource, distinguishing it from single-entity creation tools like brain_create_thought. However, 'Event+Person+Day' could be clearer, and it doesn't explicitly name alternatives, so it falls 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 phrase 'in one action' implies this is for combining multiple creations, providing a basic usage context. However, there is no explicit guidance on when to use this versus creating events, persons, or days separately, nor any exclusions or alternatives. This is implied usage, not clear guidance.

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