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

With no annotations, the description carries the full behavioral burden and does so well: it discloses idempotency semantics (retry with the same key returns the original txid), that daily limits, allowlists (spend or agent_send), and approval thresholds apply, and what txid means in each mode (BSV txid vs ledger receipt id). This is exactly the context an agent needs before an irreversible money movement.

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?

Two dense sentences with the core purpose and the destination-mode distinction front-loaded, followed by the safety/replay rules. Every clause earns its place and nothing is repeated from the schema verbatim.

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 payment tool with no annotations and no output schema, the description covers what an agent must know: the two destination modes, settlement meaning, idempotent retry behaviour, spend controls, approval gating, and the secret-vs-public id pitfall. What remains uncovered (exact limit values) is policy detail rather than invocation semantics.

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 the baseline is 3, but the description adds meaning the schema does not: it ties the dest value to settlement behaviour and txid interpretation, and explains the replay guarantee of idempotency_key at the operation level rather than just restating its type.

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 (pay) and resource (sats to a BSV P2PKH address or an apw_ wallet id), and cleanly splits the two destination modes with their differing settlement semantics. It does not explicitly differentiate from siblings like spend or pay_service, which also move funds, so an agent must infer the boundary.

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?

The destination type determines the mode (on-chain vs internal ledger), and the description makes that routing rule explicit, plus warns to pass the public wallet id and never the secret apw_ token. It stops short of naming which sibling tool to use instead when the user means a service payment or a generic spend.

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