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 useful domain context (recipients = customers configured for outbound webhooks) but says nothing about pagination, result volume, or return shape.

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?

Two tight sentences with zero waste; the core purpose is front-loaded and the follow-up sentence earns its place by clarifying downstream use of the output.

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?

For a simple one-parameter read tool with annotations covering safety and no output schema, the description covers purpose and output usage adequately. The only real gap is the unexplained appId parameter, which prevents a 5.

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 0% for the single required appId parameter, and the description only hints at app scoping with the phrase 'for an app' without naming or explaining the identifier. It fails to compensate for the coverage gap.

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 (List) and resource (customers configured to receive outbound webhooks for an app), which effectively defines what a 'recipient' is. It does not explicitly differentiate itself from the many sibling list_* tools, so it lands just short of a 5.

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?

The second sentence explains what to do with the results (use customer identifiers for endpoint and message operations), which implies usage, but there is no explicit when-to-use/when-not or comparison against alternatives like list_endpoints or list_destinations.

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