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

Annotations already indicate mutation, idempotency, and non-destructiveness. The description adds context that tracking is replaced and that the order must already be shipped, enhancing transparency without contradicting the annotations.

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 concise, front-loaded with the action, and every sentence adds value by clarifying usage boundaries.

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 simple mutation tool with no output schema, the description fully covers what the tool does, when to use it, and the key parameter behavior. No critical context 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 descriptions cover all parameters, and the description adds useful semantics such as tracking_number replacing existing tracking. The order_id status note ('awaiting fulfilment or shipped') is slightly broader than the main 'already-shipped' wording but still provides meaningful guidance.

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 verb ('Attach or update tracking') and the resource ('already-shipped order'), and distinguishes it from the sibling tool seller_mark_shipped by explicitly noting this is for late-arriving tracking only.

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?

Provides explicit usage guidance: use mark_shipped for first ship and this tool for late-arriving tracking only. This makes the tool's intended scenario clear relative to alternatives.

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