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

The readOnlyHint annotation already tells the agent this is a safe, non-mutating operation, so the description is not obligated to restate safety. It does add value beyond the annotation by disclosing the return payload — totals, transport cost, and system notes — which is the only source of that information since no output schema exists. It stops short of describing behavior for edge cases such as an empty or non-existent cart.

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?

A single sentence with no filler, front-loading the resource ('Current content of the customer's shopping cart') before the details of what comes back. Every clause earns its place by naming a distinct part of the response.

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 zero-parameter read tool with no output schema, the description carries the burden of explaining what comes back, and it does so adequately by listing contents, totals, transport cost, and system notes. It is nearly complete; only the empty-cart or no-session behavior is left unaddressed.

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 input schema declares zero parameters, so there are no parameter semantics to clarify and the baseline of 4 applies. The description correctly implies no arguments are needed by framing the tool as returning 'current' state for 'the customer', presumably resolved from session context.

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 names a specific resource (the customer's shopping cart) and enumerates the payload it exposes: contents, totals, transport cost, and system notes. It implicitly distinguishes itself from mutating siblings like add_to_cart, update_cart_item, and clear_cart because it describes retrieval of current state, though it never states a verb such as 'get' or 'retrieve' explicitly.

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?

There is no explicit statement of when to use this tool versus alternatives such as checkout_preview or get_my_order. The intent is strongly implied by the zero-parameter, read-only nature of the call, and knowing the cart's current contents is a clear precondition for add_to_cart and place_order, but the description never spells out those relationships.

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