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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral facts: secrets are never returned (so agents shouldn't expect credentials) and destination creation is out of scope for the API. Return format/pagination behavior is still 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?

Three short sentences, zero filler, with the resource and returned fields front-loaded before the two caveats. Nothing could be removed without losing 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?

An output schema exists, so return values need not be re-explained, and the description covers the key surprises (no secrets, no creation). The remaining gap is whether the result set is complete or whether page_alert_destinations should be used for large collections, which matters given that sibling's presence.

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?

The tool takes zero parameters and the schema coverage is 100%, so the baseline is 4. The description's field list ('id, kind, name, and hint') is arguably return-value information rather than parameter semantics, but it does no harm and adds context.

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 the resource (alert destinations) and enumerates the returned fields (id, kind, name, hint), so an agent knows exactly what it gets back. It also rules out creation ('Creating a destination stays in the console'), which separates it from a write path. It does not, however, distinguish itself from the sibling page_alert_destinations.

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?

Usage is only implied: the note that creation happens in the console signals this is a read-only listing, which is a useful boundary. There is no explicit 'use this when' guidance and no routing to the closely named sibling page_alert_destinations, which an agent would need to choose between.

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