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

Annotations only declare destructiveHint=true; the description adds real context beyond that — that it mutates live monitoring config, that duplicate matches return the existing check instead of erroring, and the HTTP outcomes (201 created vs 200 existing). Auth/permission requirements are not mentioned, which keeps it from a 5.

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 dense, front-loaded sentences: the mutation warning leads, then the parameter contract, then the return behavior. No filler, and the most consequential constraint (mutual exclusivity) is stated before the optional extras.

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?

With 12 optional parameters, no required fields and no output schema, the description covers the essential contract (one of timeout/schedule, dedupe, notifications) and return shape. It leaves per-field descriptions to the schema, which is fully documented, so the coverage is adequate though not exhaustive on edge cases.

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%, so the baseline is 3, but the description adds cross-parameter constraints the schema cannot express: `timeout` XOR `schedule`+`tz`, and the dedupe semantics of `unique` that control whether a create actually happens.

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+resource ('CREATES a new check') and immediately scopes it ('MODIFIES live monitoring config'), which cleanly separates it from update_check, delete_check, and the list/get siblings. An agent can identify the tool without opening the 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?

Gives concrete conditional guidance: provide `timeout` OR `schedule`+`tz` (mutually exclusive), use `unique` to avoid duplicates, assign notifications via `channels`. It does not explicitly contrast create vs update_check for an already-existing check, so it stops short of full when/when-not routing.

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