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

Annotations declare readOnlyHint=false, destructiveHint=false, idempotentHint=false and openWorldHint=false, so the safety profile is largely covered. The description adds genuinely useful non-structured context by disclosing the side effect: 'Everyone invited or coming is told.' It leaves reversibility and retry semantics unstated even though the schema exposes an idempotency_key for exactly that concern.

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?

Three short sentences with zero filler, and the core action is front-loaded before the side effect and the connection constraint. Every sentence carries distinct 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?

With no output schema, the description does the work of telling the agent what happens as a result (invitees are notified) and which connection type is valid. For a destructive-feeling mutation it still omits reversibility, failure modes (e.g., cancelling an already-cancelled event), and what the response returns, but it is substantially complete for a tool this simple.

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 67%: `artist` and `idempotency_key` are well documented in the schema, but `event_id` (the sole required parameter) has no description anywhere. The description adds no parameter-level meaning beyond what the schema already states, so the baseline 3 applies.

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 ('Cancel one of the artist's events') and scopes it to a single event, which clearly separates it from list_events and save_event. It does not explicitly name or contrast with a sibling, so it falls just short of the routing clarity a 5 requires.

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?

'Artist connections only' gives a partial condition for use, but it is the only guidance offered and it sits in tension with the schema, where the `artist` parameter is documented as 'required for every artist tool on a label connection' — implying label connections may also call this. No alternatives, prerequisites, or when-not conditions are given.

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