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

Annotations already declare write (readOnlyHint=false), non-destructive, idempotent, and closed-world behavior. The description adds the confirmation precondition, but does not explain what happens on re-add, what the idempotency_key guards, or whether the plan is per-user persistent state beyond the name.

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?

It is one sentence, so it is short, but the sentence is awkwardly nested with two conditionals ('when a user confirms' and 'only after explicit confirmation'), front-loading redundancy rather than the action.

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 3-required-parameter mutation tool with no output schema and no parameter descriptions, the description leaves too much unstated. It should at least define event_id's role and how idempotency_key is used for retry safety.

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 0%, so the description must compensate and it does not: event_id, confirmed, and idempotency_key are never mentioned. Constraints like the 16-char minimum on idempotency_key and the meaning of 'confirmed' versus the caller's assertion are left undocumented.

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 specific action (add one Dizko event to the connected user's persistent plan), which is clearer than the bare tool name. However, it is buried in a conditional clause and 'persistent plan' is vaguely defined relative to siblings like save_event or plan_night.

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 implies usage requires explicit user confirmation, but does not contrast with save_event or plan_night, which appear to be overlapping siblings. The agent cannot tell from this text alone which tool to pick when a user wants to save an event.

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