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

Annotations already declare readOnlyHint=false, openWorldHint=true and idempotentHint=false, so the description's 'WRITE:' adds little on its own. The genuinely valuable disclosure is the side effect: the day is 'created if missing' when the break is added, which is not encoded anywhere in the schema or annotations. Return values and error behavior remain unstated.

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?

A single compact sentence with the operation type front-loaded, followed by the resource, examples, and the key side-effect caveat. Nothing is redundant or padded.

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 4-parameter write tool with full schema coverage and no output schema, the description covers operation type, target resource, time semantics, and the auto-create side effect. It stops short of saying what is returned (e.g., a break identifier) or whether the event must already exist, which matters for chaining calls.

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%, so the baseline is 3; the description earns above that by clarifying that `start` does more than mark time — it determines which program day the break is placed on (and whether that day is auto-created). The optional `description` and `end` fields are left entirely to the schema.

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?

States a specific verb and resource ('add a break ... to the event program') and gives concrete examples ('coffee, lunch'), which cleanly separates it from siblings like eventee_create_session or eventee_create_hall. The 'WRITE:' prefix plus endpoint makes the operation type immediately obvious.

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 examples ('coffee, lunch') imply the use case, but there is no explicit statement of when to use this instead of eventee_create_session or how breaks relate to sessions in the program. An agent must infer that breaks are non-session program entries.

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