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

Annotations cover the read-only/open-world/safe profile, and the description adds real context beyond them: the return shape ('Each item has an ID and a name') and the auth requirement (a Cotlet API key with access to this app).

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?

Purpose is front-loaded, followed by return contents, workflow guidance, and the auth note. Every sentence earns its place; only minor tightening is possible.

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?

With no input parameters and no output schema, the description still documents the return contents, the workflow prerequisite, and the auth requirement, which is enough for an agent to call it correctly.

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 tool takes zero parameters, so the baseline is 4 and no parameter prose is required. The description correctly spends no words on non-existent inputs.

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 (List) and resource (invoice templates), and even disambiguates what a template is: 'layout and standard texts with their IDs'. This clearly separates it from siblings like create_invoice or list_invoices.

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 workflow guidance: 'create_invoice needs one template_id, so call this first.' That's a clear when-to-use pointer routed to a dependent sibling. It lacks a when-not-to-use clause, which keeps it short of a 5.

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