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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the description does not need to cover safety. It adds useful session-header context (X-Session-Id / Mcp-Session-Id), which is not present in annotations, but does not explain what happens if session is missing or what the return looks like.

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?

Extremely concise one-liner with no wasted words. It is front-loaded with the resource, though it reads as a fragment rather than a structured sentence, and could be slightly more explicit about the retrieval action.

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 is a zero-parameter read with full annotation coverage, the description provides the essential session-header hint. However, it lacks usage guidance and return-value context (no output schema exists), leaving minor gaps for an agent unfamiliar with cart semantics.

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?

There are zero parameters, so the baseline is 4. The description correctly notes that session identity comes via headers, which is relevant context even though no parameters exist.

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 is a noun phrase that identifies the resource (the session's cart) but does not state a verb or action. The tool name 'get_cart' supplies the verb, but the description itself is somewhat vague about what the tool does. It distinguishes from write siblings like add_to_cart only via the resource name, not explicit wording.

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?

No guidance is given on when to use this tool versus alternatives. It does not mention add_to_cart, remove_from_cart, update_cart_item, or any condition for selecting this read operation. Usage is only implied by the name.

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