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

No annotations are supplied, so the description carries the full disclosure burden. It does reveal the shape of the result set (per-code event history, status, delivered flag), which implies a read-only operation, but it never states that explicitly nor mentions rate limits, error behavior for unknown codes, or authentication implications beyond what the schema already says about instanceId.

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 tight sentences, correctly front-loaded with the action and resource before the return description. The trailing clause enumerating return fields slightly duplicates the existing output schema, which is the only minor redundancy.

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 an output schema present, the description need not enumerate return fields, and the input schema fully covers both parameters, so the core call path is covered. What remains thin is operational context (limits, failure modes) for a batch network-facing lookup, but nothing essential to invoking the tool correctly 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 description coverage is 100%, so both parameters (codes, instanceId) are already fully documented, including the 50-code batch cap and the tracking-code format. The description's example code and 'each code's' phrasing only restate what the schema provides, so the baseline of 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 (Track), a specific resource (Brazilian Correios objects), the identifying input (tracking code with a concrete example), and the payload returned (event history, current status, delivered flag). No sibling among diagnose_*/label tools performs tracking, so the scope is unambiguously distinguishable.

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?

Usage is only implied: an agent can infer this is the tool for looking up shipment status, but the description gives no when-to-use framing, no prerequisites, and no alternatives (e.g. what to use for label issues vs. tracking issues). Adequate but with clear gaps.

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