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

With no annotations, the description carries the full burden of behavioral disclosure. It acknowledges mutability (add/remove) but omits details like idempotency, error behavior, or whether partial failures occur. The lack of annotation makes this a significant gap.

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?

The description is a single, well-formed sentence with no extraneous information. Every word earns its place, providing efficient communication of the core purpose.

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?

Given the complexity (4 parameters, no output schema, no annotations), the description is insufficient. It fails to describe return values, error conditions, or whether the tag must pre-exist. A more complete description would cover these aspects for safe invocation.

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 50%; the description adds value by clarifying that emails or contact_ids identify contacts, and that multiple contacts are supported. However, it does not explain the relationship between these two parameters (mutual exclusivity) or the default operation value, which the schema already covers.

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 clearly states the tool adds or removes a tag to multiple contacts using emails or contact IDs. It uses specific verbs ('añade o quita') and identifies the resource ('etiqueta', 'contactos'), distinguishing it from sibling tools like update_subscriber or add_subscriber_to_list.

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?

No guidance is provided on when to use this tool versus alternatives. It does not mention prerequisites, exclusions, or context for using tag_subscribers over other subscriber management tools.

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