mail_list_messages

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

Annotations already cover readOnly and openWorld, yet the description adds real value: it confirms no read-state or mailbox mutation, and flags that message bodies are untrusted external content (a prompt-injection warning). Auth sourcing via setup-wizard is also disclosed. The size/window behavior is left to the schema.

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 purpose and ordering, then read-only behavior, then the trust warning and auth note. Every sentence carries information, though the credentials sentence could be shortened without loss.

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?

No output schema exists, but the description enumerates the returned fields (uid, sender, subject, date, read flag), and with a fully documented 3-parameter schema, ordering, safety and trust caveats, an agent has everything needed to call it correctly.

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%, with limit, folder and unseen_only fully documented in the schema itself. The description's 'los más recientes primero' only echoes the limit description and adds no new parameter meaning, so the baseline 3 applies.

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 and resource ('Lista los mensajes del correo institucional') plus the scope (newest first) and the exact fields returned (uid, remitente, asunto, fecha, leído). It implicitly separates itself from mail_read_message and mail_search by describing a bare listing, but it never names those siblings explicitly.

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?

Gives the prerequisite clearly ('Usa el usuario y la contraseña guardados con el asistente (setup-wizard)') and clarifies that it will not mark anything read, which steers away from mail_set_seen. It stops short of saying when to prefer mail_search or mail_read_message instead.

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