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

Beyond the readOnlyHint and idempotentHint annotations, the description adds 'without saving anything,' which reinforces the dry-run behavior. It also discloses the matching semantics ('All conditions must hold') and the output concept ('Count how many... match'), giving a complete behavioral model.

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?

Every sentence earns its place: the first states purpose, the second gives usage timing, and the rest fully specifies the condition syntax. There is no filler or repetition, and the most important facts are front-loaded.

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 read-only preview tool with no output schema, the description covers what it computes, when to call it, and how to structure each condition. Nothing needed for correct invocation is missing.

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?

The schema only describes the conditions array generically, but the description fully documents each condition object: the valid condition enum values, category values, threshold range, badge slug semantics, and seconds meaning. This far exceeds what the input schema provides.

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 opens with a specific verb and resource: 'Count how many of the customer's identities currently match a set of conditions'. It also states the operation has no persistence ('without saving anything'), which clearly distinguishes it from create_escalation_rule and update_escalation_rule.

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 description explicitly names when to use the tool: 'Use it before create_escalation_rule or update_escalation_rule to show the user what a rule would open.' It gives the agent a precise decision rule and names the relevant sibling alternatives.

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