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

Goes beyond the annotations by disclosing the credit cost and overage billing, the required user confirmation, the duplicate-registration failure ('Tracking No. already exists'), and the courier-specific extra field requirement. Annotations already carry the write/destructive/non-idempotent safety profile, so the description's job is supplemental and it does it well; it omits only finer points like plan limits or failure recovery.

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?

Front-loaded with the operation class and the core action, then layers cost, preconditions, failure mode, and parameters. Every sentence carries distinct, actionable information with no filler.

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 22-parameter mutation with no output schema, the description covers the required inputs, the conditional extras, the cost, the confirmation requirement, the error case, and even the return value ('the new tracking with its id'). Nothing an agent needs before calling 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 coverage is 100%, so the baseline is 3, but the description adds cross-parameter meaning: the two required fields, that courier_code comes from detect/list couriers, and that some couriers additionally need postal code, ship date, or key. This links otherwise scattered optional fields to a conditional requirement the schema alone does not express.

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 and resource ('register ONE shipment so TrackingMore starts tracking it') and pins the scope as single-shipment, distinguishing it from trackingmore_list_trackings, trackingmore_update_tracking, and trackingmore_delete_tracking. The 'WRITE:' prefix immediately frames the operation class.

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?

Explicit when-to-use with exclusions: confirm before creating, never bulk-create, and use trackingmore_detect_courier when the courier code is unknown. Alternative tools are named rather than implied.

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