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

With no annotations supplied, the description carries the full burden and does well: it declares the read-only nature explicitly ('no crea órdenes ni guías'), states the geographic domain (Venezuela), and describes what comes back (options and prices per carrier). It omits error behavior and what happens when a destination is unserviceable, which keeps it from 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?

Four short sentences in a deliberate order: what it does, what it needs, what it returns, what it does not do. The scope and inputs are front-loaded and no sentence is redundant.

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 9-parameter, no-output-schema, no-annotation tool, the description covers purpose, inputs, return content and the read-only guarantee. The main missing piece is guidance that coordinates must be resolved beforehand (the get_location/get_cities siblings exist for that), which matters given five required coordinate parameters.

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 every one of the 9 parameters is already documented, including the declared-value default behavior. The description only restates the input list (coordinates, weight, optional declared value and dimensions) without adding units nuance, format, or constraints beyond the schema — 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?

Uses a specific verb+resource pair ('Cotiza un envío') plus concrete scope: within Venezuela, using Fulfy Plus partner carriers. That scope makes it clearly distinct from the location-lookup siblings get_cities and get_location, although it never names them.

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?

It sets clear usage context (price quoting for a shipment with partner carriers) and adds an explicit negative boundary: 'Solo consulta precios: no crea órdenes ni guías.' It does not route the agent to any alternative or prerequisite (for example, that coordinates must be obtained elsewhere), so it stops short of full when/when-not/alternatives guidance.

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