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

The description discloses that the operation modifies stock and returns the product with the new remaining count, going beyond the bare annotations. It also explains the buyer-facing semantics ('Each buyer receives one'). It doesn't cover failure cases like duplicate codes, but the annotations already signal this is a mutating, non-read-only operation.

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 filler: the first names the action and resource, the second explains the purpose and return value. Every clause 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?

For a simple two-parameter tool with no output schema, the description covers the operation, the domain concept ('pool' code product), the stock effect, and the return value. It is sufficient for correct invocation, though a note about duplicate handling or uniqueness enforcement would be an added safety net.

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?

The input schema has 100% description coverage for both parameters, including 'Product UUID' and 'Unique codes/keys to append to the pool'. The tool description does not add much parameter-specific meaning, so the baseline score of 3 is appropriate.

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 states a specific action ('Add more unique codes/keys'), identifies the exact resource ('a 'pool' code product's stock'), and clarifies the purpose ('Each buyer receives one'). It clearly distinguishes this from generic add/update tools among the siblings by describing what 'product codes' means in this context.

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 clearly indicates that this tool is for adding codes to a 'pool' code product's stock, which gives a strong usage context. It does not explicitly name alternative tools or state when not to use it, so it stops short of a full 5.

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