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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=true, so the safety profile is covered. The description adds genuinely new context beyond the schema: the cross-tool prerequisite of consulting get_account for the plan's minimum interval, which behaves like a plan-tier/rate constraint.

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 sentences, front-loaded with the purpose and then the type taxonomy plus one prerequisite. Every clause maps to a real decision the caller must make; nothing is redundant filler.

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 an 11-param, no-required, nested-object creation tool the description covers purpose, type selection, and a prerequisite well. Gaps: it omits the 'redirect' type that appears in the enum, and does not state what is returned (no output schema exists, and a created check's ID matters for chaining).

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 91%, so baseline is 3. The description exceeds it by explaining type semantics the enum cannot ('rest_endpoint' supports JSONPath assertions, 'dns' means record drift, 'domain' means registration expiry), clarifying which values to pick for each param.

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 ('Create a new monitor') and immediately differentiates the tool by enumerating the eight check types and what each monitors. An agent can tell this is the creation entry point versus list_checks/get_check/update_check 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?

Gives explicit when-to-use guidance per type ('website' for a page returning 200, 'rest_endpoint' for an API, 'heartbeat' for cron jobs) and a prerequisite ('Check the plan's minCheckIntervalMinutes via get_account before setting check_frequency_minutes'). It does not state when NOT to use it (e.g. use update_check to modify an existing check), so it stops short of the 5 bar.

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