lookup_customer

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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds useful implicit scoping — the result is tied to the signed-in identity since there is no customer id parameter — but it doesn't say what happens with an unauthenticated/missing session or how many orders come back.

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 sentences, no filler, with the primary when-to-use cue placed first. Every clause carries information an agent needs to route the call.

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 no-argument read tool with no output schema, the description covers what is retrieved (profile plus orders) and when to reach for it. Order volume/truncation and authentication failure behavior are the only uncovered edges.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline applies. It implicitly explains why there are no arguments by tying the lookup to the signed-in customer.

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?

Specific verb and resource ('Get the signed-in customer's profile and a list of their orders') that also previews the return payload. It is clearly distinct from get_order, which targets a single identified order.

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?

Gives an actionable trigger plus priority ordering: 'Call this first when the customer refers to an order without giving its number, or asks about their account.' It stops short of naming get_order or track_shipment as the alternatives to use once an order number is known.

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