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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the plan-key requirement, which is genuine behavioral context an agent can act on, but says nothing about scope, pagination, or what happens on a non-Advance key beyond implying failure.

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 short sentences with no waste, and the blocking prerequisite is front-loaded ahead of the functional description. Every sentence earns its place.

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 zero-parameter read-only list tool with no output schema, the description covers the resource, its contents, and the access precondition. Only minor gaps remain, such as whether results are paginated or scoped to a workspace.

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 there is nothing for the description to clarify; baseline 4 applies. The mention of "variables" correctly signals what the returned template objects contain, though no output schema exists to confirm it.

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 (the client's approved WhatsApp templates plus their variables), which is clearly distinct from create_template and send_template. It doesn't explicitly name or exclude a sibling, so it falls just short of a 5.

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?

"Requires an Advance plan key" is a useful prerequisite that tells the agent when this call will fail, but there is no guidance on when to prefer this over siblings like send_template or get_dashboard_stats. Usage context is implied by the verb rather than stated.

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