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

Annotations already cover the safety profile (readOnly, idempotent, closed-world, non-destructive), so the description's value-add is the cost disclosure of ~140 tokens per monitor — genuinely useful for an agent budgeting context when the result set may be large. It stops short of saying what the counts represent or whether paused monitors are included.

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 labeled lines (Purpose/When/Cost) that are front-loaded and contain no filler. Every line contributes a distinct fact.

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?

An output schema exists, so return shape needn't be described, and the cost hint covers the main practical concern for a no-arg list call. Minor gap: nothing about ordering or typical result size in monitor counts.

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?

Zero parameters, so the baseline is 4; there is nothing for the description to disambiguate. The cost note implicitly warns that output volume scales with the number of saved monitors.

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 and resource plus a distinguishing detail: 'List the user's saved monitors with their counts.' That separates it from monitor_get (single monitor) and monitor_create/update/delete in the sibling set, though it never names those siblings explicitly.

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?

The 'When' line gives a concrete trigger — before choosing or changing a saved monitor — which effectively positions it as the discovery step ahead of monitor_get/monitor_update. No explicit when-not or named alternative, so not a 5.

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