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

Goes well beyond the annotations: discloses the non-idempotent consequence ('every call adds again, so do not retry blindly'), the moderate rate limit (10/min), the precondition that the reason must pre-exist, and the underlying POST /inventory/addItem endpoint. This directly reinforces idempotentHint=false and openWorldHint=true with operative detail an agent can act on.

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 tight sentences, front-loaded with the WRITE marker and the core action, then the retry hazard, then preconditions and throttle. No sentence is redundant and nothing important is buried.

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?

For a 9-parameter mutation with no output schema, the description covers action, hazards, preconditions and throttling. The only gap is that it never says what comes back (e.g., a transaction reference) after a successful add, which would help an agent confirm the write.

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%, so baseline is 3; the description earns an extra point by tying parameters to product type — serialized products need serial_numbers and lotted products need a scanned lot_code — which frames those fields as conditional requirements rather than optional fields. It adds no syntax or format detail beyond that.

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?

States a specific verb and resource — 'add quantity of a product to a warehouse location' — and immediately labels it 'WRITE', making the mutation direction unmistakable. Against siblings like skuvault_remove_stock and skuvault_set_stock_quantity, the additive semantics ('every call adds again') make clear this is incremental rather than absolute.

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?

Gives concrete preconditions (reason must already exist, serial numbers or lot code needed for serialized/lotted products) and a retry warning. It stops short of explicitly contrasting with skuvault_set_stock_quantity for cases where an absolute quantity is wanted, leaving that routing to inference from the verb.

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