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

With annotations covering the safety profile, the description still adds real value: it states the operation is reversible ('one more call sets the old number back'), that it notifies no one ('reaches no one'), that it runs without confirmation, that Bandcamp auto-decrements on sales, and the auth requirement (Cotlet API key with app access). This is unusually rich behavioral 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?

Front-loaded with the purpose and efficient overall, but the first two sentences overlap ('Set how many... available' vs 'Sets the available quantity...'), a minor 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?

For a mutation tool with no output schema, the description covers reversibility, side effects (no notifications), the auto-decrement interaction, the Sold Out edge case, and auth requirements — everything an agent needs to invoke it correctly.

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%, so the schema already documents all three parameters including the '0 marks Sold Out' and 'ID from list_merch_items' notes. The description largely repeats that content and adds no new syntax or format guidance, so baseline 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 ('Set') and resource ('available quantity of a merch item or option at a shipping origin'), and the scope (per shipping origin) distinguishes it from the read-only siblings like bandcamp_list_merch_items. An agent can tell exactly what this mutates.

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 a clear usage condition ('use this when you also sell elsewhere') and explains the auto-decrement behavior that motivates manual updates. It does not name an explicit alternative or a when-not, so it falls short of 5.

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