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

Annotations already establish readOnly/idempotent/non-destructive, yet the description adds substantive behavior: auth requirements ('Any role may read'), the precise return shape for each mode, and the critical null-vs-empty-list semantics plus per-test-over-source precedence. These are non-obvious traits the agent could not infer from structured fields.

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?

Front-loaded with the core verb and auth note, then splits cleanly into the with-id and without-id cases. It is slightly repetitive, restating the inheritance/empty-list semantics in both blocks, but every sentence still carries needed information for the two modes.

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?

There is no output schema, so the description must carry the return contract — and it does, fully specifying both response shapes, the null/empty/omitted-map distinctions, and the precedence rule. Nothing an agent needs to call and interpret this tool is missing.

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% and the single parameter's origin (list_api_tests) is already in the schema, so the baseline is 3. The description earns an extra point by tying the parameter's presence/absence to distinct return shapes, which is meaning the schema does not convey.

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 (read) and resource (where API test alerts are delivered), and immediately scopes it per-test. It clearly distinguishes itself from siblings like get_notification_destinations (source-level default), list_alert_channels (name resolution), and set_api_test_destinations (mutation). An agent can route correctly without opening any 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?

Explicitly documents the two invocation modes — with apiTestId vs without — and what each returns. It names the alternatives for adjacent needs (get_notification_destinations for the source default, list_alert_channels to resolve UUIDs, set_api_test_destinations to change routing), which is exactly the when/when-not guidance required.

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