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

Annotations only cover readOnlyHint and openWorldHint; the description adds substantial context beyond them: the three possible verdicts, the x402 cost model (~$0.005, USDC on Base or XRP/RLUSD), the free first call each day, that a payment watch is billed from the first call, and that bad input and ledger outages are never charged. This is exactly the kind of billing/eligibility behavior an agent must know before invoking.

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 check list is front-loaded, then return values, then cost, then billing exceptions - a logical order with no filler sentences. It is on the long side and the pricing detail is split across three sentences that could be tightened, but every element is decision-relevant.

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?

With no output schema, the description carries the full burden of explaining returns and it does so ('Returns ok_to_send, send_with_caution, or will_fail with reasons'). Combined with the enumerated pre-checks, billing rules, and the MPT parameter rule, an agent has everything needed to call and interpret this tool.

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 only 63%, so the description must compensate, and it does for the trickiest case: 'For a multi-purpose token, pass mpt_issuance_id instead of currency and issuer' documents a cross-parameter exclusivity rule the schema does not state. The destination-tag concept is also surfaced via the check list. Amount, source, network, and currency formats remain unexplained, keeping this below a 5.

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 ('Pre-send check for an XRP Ledger payment') and enumerates exactly what is verified (activation, destination tag, sender blocking, trust line/MPT approval, blackhole, affordability). That is far more specific than a bare title. It does not, however, differentiate itself from the sibling free_send_check or payment_check, so an agent cannot tell from the description alone which of those to prefer.

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?

'Useful before any irreversible XRP Ledger payment' gives a clear usage context and the pricing paragraphs implicitly bound when the call is worthwhile. There are no explicit exclusions and no named alternatives, notably the sibling free_send_check, which is a directly competing option an agent would want compared.

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