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

Annotations only indicate this is non-read-only and non-idempotent; the description adds substantial behavior: omitted fields keep their values, null clears description, non-string descriptions are rejected rather than silently wiping, and the return value is nested. This goes well beyond the structured annotations.

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?

Three sentences, each carrying essential information: scope, merge/validation behavior, and return shape. The most important distinction is front-loaded, and there is no filler.

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 mutation tool with no output schema, the description fully compensates by specifying the nested return shape and how to read it (result.template.name). It also covers validation behavior and the sibling alternative, so nothing critical is left unexplained.

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% and already documents each parameter's type and basic behavior. The description adds extra meaning by clarifying merge semantics, null-clearing, and the rejection of unexpected types rather than silent data loss, which earns it above the baseline.

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 the exact action — updating a template's name or description — and explicitly excludes entries, which distinguishes it from the template.set_entries sibling. The verb and resource are specific and unambiguous.

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 explicitly names the alternative when entries are involved ('not entries — use template.set_entries'), and explains the merge behavior for omitted fields. An agent can decide when to use this tool without inference.

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