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

With no annotations, the description carries the full burden. It usefully discloses what each entry contains (last message, timestamp) and that results are ordered by recency, but it says nothing about read-only safety, pagination, or whether the list is scoped to a user/workspace.

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?

A single short sentence that front-loads the verb and resource with no filler. Nothing is wasted and nothing essential is buried.

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 simple single-parameter list tool with no output schema, the description covers what is returned and the ordering, which is most of what an agent needs. It falls short only on the unstated read-only nature and result-count/pagination behavior.

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 100%, so the single limit parameter (1-100, default 20) is fully documented in the schema. The description adds no parameter detail at all, which is acceptable but earns only 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?

States a specific verb (Lista) and resource (conversas WhatsApp) plus the scope 'mais recentes'. An agent can tell it apart from get_messages in broad terms, but the description never explicitly contrasts with get_messages or search_contacts, so sibling differentiation is left to inference.

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?

There is no explicit when-to-use statement, no exclusions, and no mention of alternatives like get_messages. The phrase 'mais recentes' only weakly implies the browsing use case, so the agent gets almost no routing guidance.

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