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

Annotations already declare readOnlyHint=true, and the description adds valuable behavioral context: archived customers are included and carry 'archived: true', with the note that archiving hides nothing server-side. This clarifies a potentially surprising behavior. The description also implies pagination via schema but doesn't repeat it. Overall, it adds meaningful behavioral disclosure beyond the annotation.

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?

The description is two sentences with no fluff. The core purpose is front-loaded, and the archive behavior is succinctly appended. Every word adds value; there is no redundancy or irrelevant detail.

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?

The tool has 5 parameters and no output schema, but the schema itself thoroughly documents each parameter. The description covers the main output fields and the archive behavior. It doesn't explain the return structure (e.g., pagination fields) but the schema does, so the description is adequately complete for an agent to call it correctly. Minor gaps like mentioning the default limit are already in the schema.

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%, meaning all parameters (to, from, limit, query, cursor) have detailed descriptions. The tool description itself does not add further parameter semantics beyond what the schema provides. Per calibration, high coverage leads to a baseline of 3, and the description does not need to compensate.

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 clearly states the action ('List'), the resource ('customers'), and the specific fields returned (id, name, email, invoiced/outstanding totals). It distinguishes itself from sibling tools like list_suppliers or list_accounts by explicitly naming 'customers' and the business context. The archive behavior is also clearly noted, adding specificity.

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 does not explicitly state when to use this tool versus alternatives (e.g., list_suppliers, list_invoices). It provides context about including archived customers but offers no guidance on when this tool is preferred or when another list tool should be used. The purpose is clear, but there's no explicit routing or exclusions.

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