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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description goes beyond them by disclosing the return payload (id, paused, plan limit/used) and flagging that creation happens externally in the web app, which is genuinely useful context. Pagination behavior is unmentioned, a minor gap.

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 sentences with the core purpose front-loaded, followed by sibling routing and the external-creation caveat. Every sentence carries information; nothing is padding.

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?

No output schema or parameters exist, and annotations cover the safety profile, so the description's job is mainly to describe what comes back and how it relates to siblings. It does that adequately, leaving only pagination/volume behavior unspecified.

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, so the baseline is 4; there are no parameter semantics for the description to add or omit.

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 (Lists) and resource (the account's alert destinations), and clarifies scope by naming the channel types (Slack, Discord, non-email) and the returned fields (id, paused, plan limit/used). An agent can distinguish this from list_views and list_digests without opening a schema.

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?

Points to list_views for the related question of which Views deliver to each destination, and notes that new destinations are added in the Ticker web app rather than via any tool (there is no create_destination sibling). Clear routing context, though it never states an explicit 'use this when' trigger.

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