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

Annotations only flag it as a non-read-only, open-world, non-destructive write. The description goes well beyond that: it states the discount math scope (base price only), hard limits (no $0 releases, no 100% off), the expires_on side effect, the default per-call confirmation, and the Cotlet API key requirement with app scope. That is rich side-effect and auth disclosure.

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?

The key scoping and constraint facts are front-loaded and each sentence carries operational weight. The opening pair ("New discount code that fans enter in the Buy Now dialog. Creates a discount code.") is slightly redundant, restating the create action twice, which is the only real waste.

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 5-parameter write tool with no output schema, the description covers constraints, side effects, confirmation flow, and auth. It does not explain what the response returns (e.g., the generated code/ID), but with annotations carrying the safety profile and the schema fully documented, it is adequately complete.

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 would be 3, but the description adds genuine meaning not in the schema: that percent_off applies to the base price and never to shipping or taxes. The expires_on and name behavior largely restates schema text, so it is a modest bump rather than full semantic coverage.

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 ("Creates a discount code") plus the domain framing ("fans enter in the Buy Now dialog"). No sibling tool in the Bandcamp family creates discount codes, so the agent can immediately tell this apart from refund/update/list operations.

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 encodes real preconditions (cannot apply to a zero-priced release, 100% off not offered, percentage never touches shipping/taxes) and a confirmation workflow, which imply when the call is valid. However, it never names an alternative or explicitly frames when to reach for this tool versus other marketing/coupon operations, so usage is only implied.

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