Mua tên miền

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

Beyond the annotations it discloses a lot the schema can't: wallet deduction on VND, irreversibility (WHOIS can't be edited after purchase, hence spelling_confirmed gating), the 402 insufficient_balance path with QR display and waiting for cloud_topup_status=paid, .vn ending in pending_verification requiring cloud_domain_verify_start/wait, and sandbox=true simulating 0đ. This is far richer than the readOnly/openWorld/idempotent hints alone.

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?

It is long, but the opening sentence front-loads the core purpose and the remainder is a tight numbered pipeline where nearly every clause carries operational weight (prerequisites, error recovery, post-purchase state). Slightly dense, but not padded.

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 purchase tool with no output schema, the description still explains what comes back and what to do with it (suggested_next → cloud_app_create / cloud_domain_attach; pending_verification → verify + wait). Nothing an agent needs to invoke it correctly or handle its result 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 description coverage is 100%, so names, defaults, and the spelling_confirmed block flag are already documented; the baseline is 3. The description adds useful context (.vn needs CCCD/MST for the registrant, WHOIS is uneditable so spelling_confirmed matters) but little syntax or format detail beyond the schema.

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 description opens with a specific verb+resource+effect: "Mua tên miền và trừ ví VND — làm trọn trong phiên", and immediately distinguishes itself from cloud_domain_reserve (used when the user has no account) and cloud_domain_search (price/availability check). An agent can tell exactly what this tool does and how it differs from the other domain 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?

It gives an explicit ordered pre-flight flow (search → confirm spelling → approve cost → set registrant), names the alternative route for users without accounts (cloud_domain_reserve), and specifies error-driven branching (402 → cloud_topup → retry). Both when-to-use and when-not-to-use are covered.

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