nex_sms_release

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

Annotations already declare destructiveHint=true and idempotentHint=false, so the risk profile is known; the description adds substantive behavior beyond that: the server (not the caller) decides refunds, and the agent should refresh number and billing state before concluding. It doesn't spell out what happens to the released number's history or how an unclear release resolves, but it goes well past the annotations.

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?

Three tight sentences that front-load the action, then permissions, then caution — no filler and no restatement of the tool name.

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 tool with no output schema, the description supplies the essential safety guardrails and refund-verification loop. The remaining gap is that neither the description nor the schema explains what the reason values mean or what tel must look like.

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 0%, so the description must carry the burden, and it only indirectly illuminates the parameters: 'code timeout' and 'site rejection' map loosely to the reason enum values no_code and rejected, but the other enum values (already_registered, cannot_send_code, other) and the tel format go unmentioned. Partial compensation only.

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 opening sentence states a specific verb and resource ('Release one waiting number') plus the side effect ('request its refund'). It is immediately distinguishable from siblings like nex_sms_buy and nex_sms_code_get, which acquire or read numbers rather than release them.

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?

Explicitly names the trigger conditions ('after a confirmed code timeout or site rejection'), grants permission to act without asking again, and states a hard exclusion ('never release unrelated or user-supplied numbers'). It also gives a retry rule for ambiguous outcomes.

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