view_cart

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

With no annotations, the description carries the burden and does so reasonably: it declares read-only, and explains the semantics of three returned flags (warning, unavailable_on_depot, available_for_checkout) including what to do when they fire. It does not cover auth requirements or error behavior, but for a zero-parameter read tool the disclosure is solid.

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?

Front-loads purpose and read-only status in the first two sentences, then uses a short bulleted list for the flags and closes with the corrective action. Every line adds distinct information; nothing is repeated from the schema.

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-param read tool with an output schema, the description supplies exactly what structured data cannot: the meaning of each readiness flag and the remediation path. An agent has everything needed to call it and act on the result.

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 the schema-vs-description comparison is moot and the baseline of 4 applies. The description correctly spends no words on arguments and instead explains the returned flags.

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 and resource ('Show the current cart contents and running total') and adds scope detail (order-readiness reporting) that separates it from siblings like checkout_preview and clear_cart. The read-only framing plus the named sibling update_cart_item makes its role unambiguous.

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 clear context (call it to inspect the cart and its order-readiness) and routes the agent to the alternative when problems appear: 'Remove/replace flagged items with update_cart_item(product_id, 0) before checkout.' There is no explicit when-not or timing statement beyond the implicit pre-checkout use.

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