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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description adds useful behavioral context by listing the returned fields (status, items, carrier, tracking, ETA) and the privacy guarantee that no personal details are returned. It stops short of covering access failures or error behavior for a bad order/email pair.

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?

Two tight sentences: the lookup scope and inputs come first, the return payload second, and the privacy caveat last. No filler or repetition of the title.

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?

With no output schema present, the description usefully enumerates what is returned, and it identifies both required parameters. A minor gap is that it does not state what happens on a non-matching order/email (error vs empty), but for a simple two-param read this is close to complete.

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 0%, so the description must carry both parameters — and it does: order_no is clarified with a concrete format example (ST2610010001) and email is clarified as the address used at checkout. That meaning is not derivable from the bare string types in the schema.

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 (look up) and resource (an order) plus the exact inputs needed (order number like ST2610010001 and checkout email). It also enumerates the returned fields, so an agent can distinguish it from the cart/checkout/product siblings at a glance.

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?

Usage is implied by the required identifier pair — you call this when you have an order number and email — but the description names no alternatives or when-not conditions. Since no sibling tool overlaps this purpose, the omission is not costly, but no explicit routing guidance is given.

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