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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuinely new context: the authenticated-ownership requirement and the fact that both a missing id and a foreign-owned id collapse to the same 'not found' response, which is valuable for error handling.

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?

Four tight sentences, front-loaded with purpose, then the status vocabulary, the repeating-event rule, and error semantics. No filler, though the status values repeat the schema enum and could be dropped.

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?

An output schema exists, so return values need not be described. Combined with annotations covering the mutation profile, the description covers ownership/auth scope, the conditional occurrence parameter, and error behavior — everything an agent needs to invoke it correctly.

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 100%, so the baseline is 3, but the description goes beyond the schema by explaining the effect of occurrenceDate ('so only that day changes') rather than merely restating its type. The status enum is duplicated from the schema, which adds no new information.

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 (Set status) and resource (event owned by the authenticated user), plus the exact enum of resulting states. It is clear what it does, though it never contrasts itself with sibling update_event, which could plausibly also alter status.

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?

Gives explicit conditional guidance for the optional parameter: pass occurrenceDate for a repeating task so only that day changes. It also scopes usage to events owned by the caller. It stops short of naming an alternative (e.g. update_event) or stating when this tool should not be used.

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