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

Annotations indicate a non-read-only, non-destructive mutation, so the safety profile is partly covered. The description adds useful context about what the channel controls (checkout code, register voucher, or shopper choice), but it omits auth requirements, idempotency, and whether changing the setting affects existing vouchers or checkout codes.

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?

A single front-loaded sentence with no wasted text. The parenthetical clarifications for each mode are compact and directly useful.

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 one-parameter setter with annotations covering the mutation safety profile and no output schema, the description supplies the key channel semantics needed to call it correctly. It does leave minor operational gaps around prerequisites and effects on existing settings, but the low complexity keeps it broadly 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?

There is only one parameter and schema coverage is 100%, so the baseline is 3. The description adds meaning beyond the schema by explaining that online means a checkout code, offline means a voucher at the register, and both means the shopper chooses.

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: 'Set how this store's customers spend loyalty points', and names the available channel modes. It is clear what setting the tool controls, though it does not explicitly contrast with nearby program-configuration siblings.

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?

Usage is implied by the setting's scope, but the description gives no explicit when-to-use guidance, prerequisites, or alternatives such as update_program_config. An agent can infer that this is the store-level channel setter, but the routing is not spelled out.

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