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

With no annotations, the description carries the full burden and does so well: it discloses the scope of mutation, the deliberate exclusion of subscription state, the audit semantics of confirmar_resuscripcion, and the actual runtime failure (403 resuscripcion_no_disponible_para_agentes). It stops short of stating permission/auth requirements or the response shape, so not a 5.

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?

Front-loaded with the core purpose and the field scope, then the alternative-tool routing. The final sentence is dense with an API path and error code, but that content is load-bearing (it explains the agent-only restriction) rather than padding.

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 no annotations, no output schema, and 0% schema description coverage, the description supplies the safety and boundary context an agent needs to call this correctly. The only real gaps are the required email identifier and the shape of the return, which are minor for an update tool.

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 0% across 6 parameters, so the description must compensate. It names four fields (first_name/last_name as "nombre", country as "país", phone as "teléfono", tags as "etiquetas") but omits the required email parameter and gives no format hints for tags or country codes.

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+resource ("Actualiza datos de un contacto existente") and enumerates the editable fields (nombre, país, teléfono, etiquetas). It distinguishes itself from state-change tools by clarifying it does not alter subscription status, though it doesn't explicitly differentiate from other writers like tag_subscribers or update_* siblings.

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?

Explicitly states when to use it, what it will not do ("no cambia su estado de suscripción"), and names a sibling alternative (reactivate_bounced_subscriber) with its own trigger condition. It also spells out the case where no agent action is possible (unsubscribed/spam contacts) and why, which is unusually complete routing guidance.

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