Leer un mensaje

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

Adds substantial context beyond the annotations: it discloses the return shape (trimmed plain text plus attachment list), the conditional side effect ('no lo marca como leído salvo mark_seen=true'), and a 2 MB truncation rule that omits the body. This clarifies why readOnlyHint=false despite the read-shaped name; only error/timeout behavior is left unstated.

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?

Four short sentences, each carrying distinct information (purpose, output, side-effect condition, size limit), with the core action front-loaded and zero filler.

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?

With no output schema, the description responsibly covers the return contents, the side-effect condition, and a size cutoff, which is close to complete. Minor gaps remain around mailbox defaulting and failure behavior, but nothing critical for a correct call is missing.

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%, with uid and mark_seen already described in the schema. The description reinforces the mark_seen conditional and implies max_chars via 'texto plano recortado', but says nothing about the mailbox parameter, leaving part of the gap uncovered.

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 ('Lee un mensaje por UID') and clarifies the scope as a single-message fetch keyed by UID, which implicitly distinguishes it from list_messages/search_messages. It does not explicitly name any sibling, so it stops short of full differentiation.

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 when-to-use guidance and no mention of alternatives such as list_messages, search_messages, or save_attachment. The mark_seen caveat is a behavioral note, not routing guidance, so an agent gets no help deciding when this tool is the right pick.

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