get_cart

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

With no annotations provided, the description carries the full behavioral burden. It explicitly discloses that this operation reads without changing anything, which is the key side-effect guarantee an agent needs. It does not mention edge cases like an empty cart or unauthenticated state, but for a simple getter the essential behavioral trait is well covered.

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, front-loaded sentence with zero filler. Every word earns its place: it states the action, the resource, the authentication context, and the non-mutating guarantee. This is exemplary conciseness without sacrificing content.

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?

Given the tool's low complexity (no parameters, output schema present), the description is nearly complete. It covers purpose, target resource, authentication context, and read-only behavior. It could marginally improve by pointing to auth_status for authentication failures or update_cart for modifications, but nothing essential is missing for a correct basic invocation.

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 has zero parameters, and the schema coverage is 100% by vacuity. The baseline for 0-parameter tools is 4, and the description needs to clarify no arguments or input requirements, which it effectively does by needing none. No additional parameter semantics are required.

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 verb ('Read'), a specific resource ('the current authenticated Mercadona cart'), and explicitly states 'without changing it', which distinguishes it from the sibling update_cart. There is no ambiguity about what this tool does.

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?

The description implies the use case: retrieving the current cart state read-only. However, it never explicitly names sibling tools or conditions, such as using update_cart when modification is needed or auth_status to verify authentication. Usage context is clear but exclusion/alternative guidance is only implicit.

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