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

With no annotations, the description carries the burden of behavioral disclosure. It states the effect (change quantity, remove at 0) and the return value (updated basket). It does not mention error handling or side effects beyond the direct mutation, but for a simple update tool this is adequate and not contradictory.

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?

The description is two sentences with no filler. It front-loads the core action, then states the removal behavior and return value, all in an efficient structure.

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?

The tool is simple with 3 required parameters and no output schema, but the description notes the return value. It covers the primary use case and behavior, though it omits error scenarios or explicit guidance on when not to use it. Given the low complexity, this is reasonably complete.

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 100%, so each parameter is already well-documented in the schema (e.g., item_id is the basket line ID from view-basket, quantity is the new quantity, 0 removes). The description adds no additional semantics beyond what the schema provides, so it meets the baseline for high coverage.

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 uses a specific verb ('Change') and resource ('basket line'), and clarifies the special case of quantity 0 removing the line. It clearly distinguishes from siblings like remove-from-basket and add-to-basket by focusing on quantity updates.

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 when to use the tool (to update quantity) and notes the removal behavior, which indirectly differentiates it from remove-from-basket. However, it does not explicitly state alternatives or exclusion conditions, so it falls short of a perfect score.

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