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

Annotations only carry destructiveHint=true, so the description does the heavy lifting: it discloses partial-update/merge semantics, the read/write auth requirement, and a concrete destructive hazard (re-sending a read-only-key URL erases hidden basic-auth credentials). That is precisely the kind of beyond-annotation context an agent needs before mutating state.

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 action and field list, then the merge rule, the caution, and finally the auth/endpoint. Every clause carries information, though the credential caveat and API-key sentence could be tightened slightly.

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 14-parameter mutation tool with thin annotations and no output schema, it covers the essentials: scope, merge behavior, auth, and a data-loss warning. Return-value/pagination detail is unnecessary here since no output schema exists, leaving only minor gaps.

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 schema baseline is 3, but the description adds real meaning by mapping fields to intents (enabled = pause/resume, mute_until = mute alerts) and summarizing the category of settings covered. It does not add syntax detail beyond the schema, so it lands just above baseline.

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?

Specific verb plus resource ('Change a check's settings') with an enumerated list of updatable fields and the distinct pause/resume and mute sub-actions. It is immediately separable from updown_create_check, updown_get_check, and updown_list_checks.

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 the key operating rule ('Only the fields you pass are changed') and states the credential requirement ('Requires the read/write API key'), which is exactly the gate an agent needs before calling. It stops short of naming alternatives such as updown_get_check for read-only inspection, so it is clear context without explicit exclusions.

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