detect_carrier

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

The description discloses behavioral traits: best effort, confident only for certain formats, returns fallback with confident=False for ambiguous numbers. Since no annotations are provided, the description carries the full burden and does so adequately.

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 extremely concise, front-loading the main purpose in the first sentence, and uses an Args section efficiently for the single parameter.

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 simplicity, the description provides sufficient behavioral detail and limitations. It mentions the confident flag, though it could be slightly more explicit about the return format.

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?

The only parameter 'tracking_number' is described as 'The number to classify,' which adds minimal meaning beyond the schema. With 0% schema description coverage, the description compensates partially but not richly.

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 guesses the carrier from a tracking number format, mentioning specific carriers (UPS, DHL) and distinguishing it from siblings like list_carriers and track_parcel.

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 provides clear context on when to use the tool, indicating it is for classifying a tracking number, and describes behavior like fallback carrier and confidence flag, but does not explicitly mention when not to use or alternatives.

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