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

Annotations already flag destructiveHint=true, so the bar is lower, yet the description adds substantial context: copies are removed from target calendars while source events are untouched, the action is irreversible, removal happens in the background within minutes, and it costs no credits. It also discloses the token-gating behavior ('without a valid, unexpired token for exactly this sync nothing is deleted').

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 tight paragraphs: purpose+workflow, then destructive scope, then side effects and alternatives. Front-loaded with the verb and the confirmation requirement; no sentence is filler given the safety-critical nature of the tool.

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 an output schema present, return-value explanation is unnecessary, and the description covers everything else an agent needs: prerequisites, token semantics, what is destroyed, what is preserved, reversibility, timing, and cost. Nothing material is missing for a destructive mutation tool.

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 baseline is 3, but the description adds real meaning to confirmation_token: it must be valid, unexpired, and scoped to exactly this sync, and ref must match the one used in preview_delete_sync. That is semantic detail genuinely beyond the schema's terse 'from preview_delete_sync' text.

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?

Opening sentence states a specific verb and resource ('Deletes one of the user's own syncs') and the scope ('own' syncs). It is clearly distinguishable from siblings preview_delete_sync (the prerequisite step) and set_sync_paused (named as the non-destructive alternative).

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?

Explicit workflow: call preview_delete_sync first, report the sync and copy count to the user, then call only after explicit in-chat confirmation. It also names the correct alternative ('to only stop syncing, use set_sync_paused instead') and warns against prompt-injection triggers, which is exactly the when/when-not guidance an agent needs.

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