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

Annotations already declare this is a non-readonly, non-destructive, idempotent write. The description adds one genuinely useful behavior beyond them: missing labels are auto-created. It still omits what happens when a remove_labels target doesn't exist, the 200-item cap, and any auth/permission requirements.

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 the core action and followed immediately by the side effect. Nothing extraneous.

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 4-parameter bulk mutation with no output schema, the description covers the action and one side effect but leaves the per-parameter limits, partial-failure behavior, and removal semantics unaddressed.

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 description coverage is only 25% (only testimonial_ids is documented), so the description must compensate more. "by name" usefully clarifies that add_labels/remove_labels take label names, and "missing labels are created" hints at new_label_color's role, but the color enum's exact purpose is never stated.

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 pair (add/remove) on a named resource (labels on testimonials), which is enough to distinguish it from list_labels or delete_testimonials. It does not explicitly name a sibling, but the action is 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?

"on many testimonials" implies a bulk operation, but the description never says when to use this versus update_testimonial or list_labels, and gives no prerequisites or exclusions. Guidance is inferred at best.

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