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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world), so the description adds incremental value: it discloses data freshness ('latest validated ledger only') and that it is not historical or price-oriented. It does not discuss caching, rate limits, or what the congestion score means, so it is useful but not exhaustive.

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 short, labelled sentences plus an example, with the payload description front-loaded and no filler. Every clause earns its place by either stating scope or excluding a wrong interpretation.

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 an output schema present, return-value detail is not required, and the description covers purpose, timing, freshness, and exclusions for a zero-param read. The only minor gap is that the semantics of the 'congestion score' scale are left entirely to the output schema.

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?

The tool takes zero parameters, so the baseline is 4. The description appropriately spends no space on parameters and instead includes a call example ('xrpl_fee {}'), which is the only parameter-relevant information possible here.

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 names the resource (XRPL fee tiers), the unit (drops), and an extra returned signal (congestion score) in one line. It further distinguishes itself from siblings by stating it is 'not a price feed and not a historical series' and covers 'the latest validated ledger only'.

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 trigger ('before submitting a transaction, to choose a Fee and to decide whether the network is congested') and an explicit negative scope ('Prefer another tool: Not a price feed and not a historical series'). This routes an agent without requiring it to open any other schema.

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