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

readOnlyHint=true already covers the safety profile, so the description only needs to add context. It contributes the underlying API call (GET /api/recipients) and the id format returned, but says nothing about pagination, result size, or authorization — modest incremental value over the annotations.

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 compact sentences, front-loaded with the resource and scope, then the id explanation, then the endpoint reference. No filler or repetition.

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 zero-parameter read-only tool with no output schema, the description conveys what entity is listed and the key identifier shape the caller will need. It stops short of describing the result envelope or whether results are paginated, which is the only meaningful gap.

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 per the rubric the baseline is 4. The description's mention of id syntax describes return data rather than inputs, and no input semantics are needed here.

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 gives a clear verb+resource ('List the alert recipients/channels on the account') and enumerates the channel types (email, sms, slack, telegram, webhook, zapier), which makes the returned entity concrete. It does not explicitly differentiate itself from the sibling updown_add_recipient, but the list-vs-add distinction is obvious from the name and verb.

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 the `id` (e.g. email:3719031852) 'is what check `recipients` take' hints this is the step you run before creating/updating a check's recipients. There is no explicit when-to-use, when-not-to-use, or named alternative among the 13 siblings.

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