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

No annotations are provided, so the description carries the full burden. It discloses a key behavior: automatically scanning email for tracking numbers. It also lists supported carriers. However, it does not clarify whether the operation is read-only, what permissions are needed, or what occurs if no tracking numbers are found. This partial disclosure leaves significant gaps.

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 two concise sentences, front-loaded with the core purpose. There is no fluff; every word contributes to understanding the tool's function and scope.

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?

The tool has no output schema and no annotations, so the description must cover behavior and returns. It explains the purpose and carrier support but omits what the response looks like, how results are presented, and prerequisites like email access. For a tool that relies on scanning email, more context is needed for full usability.

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% since only 'tracking' has a description. The tool description lists carrier names (UPS FedEx USPS Amazon DHL), which hints at valid values for the 'carrier' parameter but does not explicitly map it. It also does not explain the relationship between parameters, such as whether 'carrier' is needed when 'tracking' is provided. The description adds some value but does not fully compensate for the coverage gap.

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 begins with 'Track package delivery,' a specific verb+resource statement. It further clarifies by stating it scans email for tracking numbers automatically and lists supported carriers. This distinguishes it from sibling tools like track_flight, which handles a different domain.

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 implies usage by noting it scans email automatically, suggesting the tool can be called without parameters. However, it does not explicitly state when to use this tool over alternatives, nor does it mention exclusions or prerequisites. The context is present but not fully developed.

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