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

Annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, so the mutation profile is covered. The description adds genuinely new behavior: removal is immediate on this call without a separate confirm, the remaining cart is returned, and a specific failure mode is `ErrorResponse(line_not_found)`. It does not mention auth or whether removal can be undone, so not a 5.

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?

Three short sentences, front-loaded with the action, followed by the trigger and the failure case. Nothing is redundant and no sentence could be dropped without losing signal.

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?

With an output schema present, the description need only cover the action, trigger, and notable error, all of which it does, and annotations carry the safety profile. The remaining gap is the undocumented parameters, which the schema leaves entirely bare.

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?

Schema description coverage is 0%, so both `session_id` and `line_id` are undocumented in the schema itself. The description references `line_id` only obliquely through the error case and implies a session-scoped cart, which is helpful but leaves the meaning and format of `session_id` unexplained.

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 gives a concrete verb and resource ('Remove a line from the session cart') and states the return value, which sets it clearly apart from the read-only order_view_cart sibling. It stops short of naming any alternative directly, so differentiation is inferred from the verb rather than stated.

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?

'Call it when the customer asks to drop the line' supplies an explicit trigger condition, and 'their request is the go-ahead, and the line is removed on this call' pre-empts a redundant confirmation step. No when-not conditions or named alternatives are given, which keeps it below a 5.

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