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

With no annotations, the description carries the full burden. It discloses the output format: 'Returns current status with Thai label plus the event history.' It also explains the auth behavior. It does not cover rate limits, error handling, or data freshness, but the provided details are sufficient for a low-complexity tool.

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?

The description is three sentences long, each serving a distinct purpose: purpose, output details, and auth context. It is front-loaded with the core action and avoids any wasted words.

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?

Given the tool's low complexity (1 required parameter, no output schema, no nested objects), the description adequately covers purpose, output, and authentication. It could be improved by mentioning error handling or invalid tracking numbers, but it is complete enough for an agent to use 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 description coverage is 100% (tracking_no is described with an example). The description adds no additional semantic meaning beyond the schema; it merely restates the purpose. Per the baseline rule for high coverage, a score of 3 is appropriate.

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?

The description clearly states the tool's purpose: 'Track any parcel by tracking number' and specifies carriers (Thailand Post and other Thai carriers). It distinguishes well from sibling tools like create_order, cancel_order, etc., which are order management functions.

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?

The description gives clear context for when to use the tool – to track parcels. It also provides authentication guidance: 'Works without auth if the server has a tracking token configured; otherwise pass your Bearer token.' However, it does not explicitly state when not to use it (e.g., for non-Thai carriers) or mention alternatives.

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