Conectar cuenta de MercadoLibre

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

The description explicitly says the tool links an account and 'completa la conexión' — a credential/token write — while annotations declare readOnlyHint=true. That is a direct contradiction that could mislead an agent about side effects. Valuable context it does add (env-var prerequisites, browser-based flow) is overshadowed by the inconsistency.

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?

Two short sentences: the two-mode behavior first, then the environment prerequisite. No filler, and the most decision-relevant information (no-arg vs. code) is front-loaded.

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 2-optional-parameter, no-output-schema tool it covers the essential flow and the return of the no-arg case (the URL). It leaves out the `sitio` option and what confirms a successful connection, small gaps given the low complexity.

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 both parameters are already documented in the schema; baseline 3 applies. The description adds flow-level meaning to `code` (it comes from the authorization page) but never mentions `sitio` at all, so it adds little beyond structured fields.

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 ('Vincula una cuenta de MercadoLibre') and immediately distinguishes its two operating modes (no-arg returns an auth URL; with `code` completes the link). An agent can tell it apart from siblings like ml_desconectar or ml_cuentas without opening the schema.

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?

Clear conditional routing: call without arguments to obtain the browser authorization URL, call with `code` once the user has authorized. It also names the prerequisite (ML_APP_ID / ML_APP_SECRET must be configured). It does not name a sibling alternative to use instead when already connected, which keeps it short of a 5.

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