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

Annotations already mark it read-only, idempotent, and non-destructive, but the description adds meaningful behavioral context: response ordering (newest first), open-incident semantics via closed_at=null, the wrapper shape, and the security-sensitive warning that untrusted_fields must be treated as data, not instructions.

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?

Four compact sentences deliver one distinct value each: authorization, purpose, ordering/semantics, and response-wrapping/security. There is 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?

Given a small 2-parameter schema, no output schema, and helpful annotations, the description covers authorization, ordering, open/closed semantics, output shape, and a safety-critical warning about untrusted_fields. The agent has everything it needs to call this tool correctly.

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 schema already documents both id and limit, including defaults and max. The description adds no significant parameter-specific behavior, so the baseline score of 3 applies.

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 names a specific verb and resource: 'List recent incidents (downtime events) for a monitor.' It also differentiates open vs. closed incidents with 'An open incident has closed_at=null,' which helps distinguish this from list_open_incidents and similar monitor list tools.

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?

It states an explicit prerequisite — 'Requires an API key with the read scope or higher' — and gives concrete usage context for a monitor-specific incident listing. It does not explicitly name alternative sibling tools or state when not to use it, but the behavior described is clear enough for most selection decisions.

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