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

Annotations only declare readOnlyHint/openWorldHint, but the description adds substantial undisclosed behavior: the x402 payment model (first call per day free, ~$0.01 after, USDC/XRP/RLUSD), that payment watches are billed from the first call, and that bad input and outages are never charged. It also warns that issuer-written metadata is quoted rather than asserted as fact and that missing asset classes are reported as missing.

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?

Purpose and scope are front-loaded in the first two sentences, followed by exclusions and then billing terms; every sentence carries information an agent needs. The pricing sentences are slightly repetitive (free first call, paid watch, no charge on failure) and could be tightened without meaning to earn a 5.

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 three-optional-parameter, read-only, no-output-schema lookup, the description covers what is returned, what is deliberately not covered, the disclosure stance on issuer metadata, and the cost model. Nothing an agent needs to decide to call it or to interpret the 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% and the schema already states the currency-needs-issuer rule and the "use this or currency plus issuer, not both" exclusivity for mpt_issuance_id. The description restates the same parameter relationships without adding format or edge-case detail beyond the schema, so the baseline 3 applies.

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: identify one XRP Ledger token, distinguishing the two supported forms (trust-line via currency+issuer, MPT via 48-hex issuance id). It also enumerates exactly what is reported (type, issuer domain check, supply, freeze/lock/clawback/restriction controls), which cleanly separates it from siblings like issuer_check or token_types.

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 accepting an MPT or any other token" gives clear when-to-use context, and it explicitly excludes other chains, legal backing, and solvency. It stops short of naming sibling alternatives (issuer_check, token_types) for the cases it does not cover, so routing is implied rather than fully specified.

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