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

Annotations already indicate a non-read-only, non-destructive operation, and the description adds valuable behavioral context: the Owner/Admin permission requirement and the ISO-8601 format for date-time parameters. This goes beyond the annotation defaults.

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 sentences, front-loaded with the core action, then essential constraints. No fluff or redundancy; every sentence contributes meaningful information.

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 the output schema exists (so return values need not be described), the description covers the core action, permissions, and date format. It does not discuss error cases or side effects, but for a relatively simple add-operation with annotations and schema, it is sufficiently complete.

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% since all five parameters have descriptions. The description's note about ISO-8601 repeats what the schema already states, adding no new semantic meaning beyond the structured fields. Baseline of 3 is appropriate.

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 'Add a new event to the guild's shared calendar' with a specific verb and resource, distinguishing it from sibling tools focused on other entities like campaigns or mnemons. The 'guild calendar event' scope is 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?

It provides clear context by noting 'Owner/Admin only', which indicates when this tool can be used. It does not explicitly mention exclusions or alternatives, but the resource specificity and permission hint give adequate usage guidance.

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