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

Annotations already declare destructive=true, idempotent=false and openWorld=true; the description goes well beyond by stating that Channable forwards the change to the marketplace, that it cannot be undone through this API, that the call is never retried, and what to do after a timeout. That is exactly the retry-safety context an agent needs for a non-idempotent mutation.

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?

Four compact sentences, front-loaded with purpose then constraints, with the endpoint appended rather than leading. Slightly dense, but every sentence carries distinct information and nothing is redundant.

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 destructive, non-idempotent mutation with no output schema, the description covers marketplace support, data shape, irreversibility, retry semantics, and timeout recovery. Nothing an agent needs to invoke it safely is missing.

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 the baseline is 3, but the description adds real meaning: it clarifies that 'products' holds the order item ids (not catalogue SKUs) and that the status field is optional. This resolves the main ambiguity an agent would have when populating the nested array.

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+resource ('Manually create a return on the marketplace for products of an order') and scopes it to four marketplaces, which distinguishes it from sibling tools like channable_update_return_status and channable_get_return. An agent can identify exactly what this does without opening the schema.

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 phrase 'Manually create a return' and the explicit marketplace allowlist (Fruugo, Otto, Veepee, Zalando) give clear conditions for when this tool applies and when it will not. It does not explicitly contrast against channable_update_return_status, but the manual-vs-status distinction is implied.

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