update_inventory_quantity

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

With no annotations, the description carries the full burden. It labels the tool as a 'guarded write', implying cautions, and clarifies it is a stub, so calls will not actually modify data. This adds valuable behavioral context beyond a simple 'update' description.

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?

Two sentences with no unnecessary words. The first sentence front-loads the core purpose and safety class. The second sentence concisely conveys a critical behavioral constraint and context.

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 description does not explain the return value, the expected structure of the 'changes' parameter, or any prerequisites for the guarded write. Given 5 parameters and no output schema, the description leaves gaps that the agent must infer.

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%, but the descriptions in the schema are generic (e.g., 'High-level desired changes'). The tool description adds no additional parameter meaning or formatting guidance, so it stays at the baseline of 3.

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 clearly states 'Update seller-fulfilled listing quantities', which is a specific verb-resource pair. The prefix '[Catalog / guarded write]' adds domain and safety context. This distinguishes it from other update tools (e.g., update_price, update_listing) and other inventory tools.

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?

Explicitly states 'Hosted endpoint only; this local stdio server is an introspection stub.' This tells the agent not to use it on this server. Additionally, 'seller-fulfilled listing quantities' implies it is for MFN, not FBA, guiding the choice among sibling tools.

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