market_cart_update

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

No annotations are provided, so the description carries full burden. It discloses the removal behavior via quantity=0 but does not mention side effects, error conditions, authorization requirements, or rate limits. For a mutation tool, more behavioral context is needed.

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 extremely concise: two sentences that directly convey the purpose, a key usage note, and a versioning hint. Every word earns its place with no redundancy.

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 low complexity (2 simple params, no output schema, no annotations), the description covers the core operation. However, it lacks information about what happens on success (e.g., return value), error conditions (e.g., invalid product_id), or prerequisites (e.g., product must be in cart). For a complete understanding, an agent would need to infer or test.

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 coverage is 100% but the description adds significant value: the '[Shop]' prefix provides domain context, the note about quantity=0 clarifies the removal functionality, and the replacement note gives historical context. This goes well beyond what the schema provides.

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?

Clearly states the action 'change item quantity' and the resource 'cart'. The description also specifies the special case of quantity=0 for removal and mentions it replaces a previous sibling (market_cart_remove), effectively distinguishing it from related tools even though market_cart_remove is not in the sibling list.

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?

Provides explicit guidance on using quantity=0 to remove items, which is a key use case. It also references the replacement of market_cart_remove, offering context. However, it does not explicitly state when not to use the tool or provide alternatives beyond the removed tool, though the sibling list is extensive.

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