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

With no annotations, the description carries the full burden and does well: it declares the call free, quantifies the Xahau facilitator fee (flat 0.01 XAH, paid as a second Payment), and names the exemption (SML endpoints) and the rail with no fee (XRPL). It omits whether the invoice is persisted, whether it expires, and any auth requirements, which a mutation-adjacent tool would ideally state.

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?

Front-loaded with what the tool returns, then rail routing, then fee behavior. Dense but every clause carries operational information an agent needs to pick parameters or predict cost; nothing is padding.

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?

No output schema exists, and the description compensates by naming the returned fields (destination address, amount, payment_options, and the fee_* set on Xahau third-party endpoints). That covers selection and expectation-setting; remaining gaps are lifecycle details like invoice expiry and idempotency.

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 100%, so the per-parameter baseline is a 3; the description earns above that by documenting cross-parameter combinations the schema cannot express individually (currency plus chain for Solana, asset or chain for Xahau). It does not add format or validation detail beyond the routing rules.

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 and resource ('Request a payment invoice') scoped to 'any SqueezeOS endpoint', and lists the concrete rails it covers. An agent can distinguish this from verify_payment or get_compliance_receipt without opening any schema.

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?

Gives explicit parameter routing for each rail ('currency=USDC and chain=solana for Solana', 'asset=XAH (or chain=xahau) for Xahau'), which is real selection guidance. It stops short of naming when to use this versus sibling tools such as verify_payment, so no exclusions or tool-level alternatives are stated.

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