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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description adds genuinely new behavioral context: templates contain placeholders, {{name}} is auto-filled from the saved contact name, and some connections may be restricted to template-only sending — details not present in any structured field. It stops short of noting ordering or whether all templates are always returned.

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 tight sentences, front-loaded with what the tool returns and then the downstream action. Slightly telegraphic ('Some connections may send only these'), but no sentence is wasted.

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 fields need no explanation, and read-only annotations cover the safety profile. The description supplies the one thing structured data cannot: what a template is and how to use it — though it leaves vague what 'some connections may send only these' concretely implies for the agent.

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. The description's discussion of {{name}} and 'vars' is about template placeholders consumed by send_sms rather than this tool's inputs, but it is still relevant context for using the results correctly.

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 states a specific resource ('The user's saved templates') and characterizes what a template actually is ('approved wording with {{blanks}}'), which is more than the title alone provides. It lacks an explicit verb like 'list', but the resource and its nature are unambiguous and clearly distinct from siblings such as list_messages or get_stats.

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?

It implies the workflow ('Send one with send_sms template_id and vars'), so an agent can infer this is the discovery step before send_sms. However, it never explicitly says when to call this tool versus other listing tools, nor any condition or exclusion beyond the vague 'Some connections may send only these'.

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