check_availability

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds value beyond that by disclosing the exact response shape (yes/no plus enumerated reasons: out of stock, insufficient quantity, inactive, unknown SKU), which an agent needs to interpret results. It omits any auth or rate-limit context.

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 compact sentences, front-loaded with the core question, then the return contract, then the usage trigger. No filler; every sentence earns its place.

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?

An output schema exists, so return values need not be re-explained, yet the description still summarizes the reason codes usefully. Annotations cover safety and the schema covers parameters, so the definition is nearly complete; the only minor omission is any hint about latency, batch limits, or behavior when a location name is invalid.

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% – both 'lines' and 'location_name' are documented in the schema, including the 25-line cap and the location scoping behavior. The description adds no parameter-level meaning beyond that, so the baseline of 3 applies.

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 ('Can these SKUs be sold right now?') and explicitly enumerates the return semantics (sellable yes/no with a per-SKU reason). It is clearly distinguishable from generic item tools like list_items or get_item because its purpose is sellability, not retrieval.

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 an explicit trigger: 'Call this before an agent pitches, recovers or promises any product to a customer.' That is strong when-to-use guidance. It does not name when not to use it or point to a sibling for the alternative case, so it falls short of a 5.

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