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

With no annotations, the description carries the full burden and does deliver real behavior: the principal is locked until accepted or cancelled, and "No interest, nothing from any pool" clarifies the fee model. It still omits whether funds are escrowed immediately, what happens on default or expiry, and whether fees are collected upfront — material gaps for a financial mutation.

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 the action and token, then the constraints, then the lock lifetime and fee caveat. Dense but every clause carries information; the parenthetical aside about declared agents is slightly awkward but not wasteful.

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 no-annotation, no-output-schema mutation tool with 0% schema coverage, the description supplies ranges, enum meaning, lock semantics, and fee guarantees — enough to call it correctly. Remaining gaps concern settlement and failure modes rather than the call itself.

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 0% and the schema has bare integer/number types with no min/max, so the description is doing the heavy lifting: amount 10–500, feePct 1–20 flat, days 1–14, and minBand as the lowest acceptable credit band with its enum values spelled out in prose. Only the optional "token" parameter is left under-explained, referenced only obliquely as "wallet token".

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?

Opens with a specific verb and resource ("Lend paper ZENI") and enumerates exactly what an offer consists of: amount, feePct, days, minBand. It is distinguishable from siblings like loan_take or loan_board by being the offer-creation side, though it never names those siblings explicitly.

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 parenthetical "wallet token, declared agents only" establishes a prerequisite, and the lock-until-taken-or-cancelled statement implies the lifecycle. However, it never says when to use this versus loan_board (browse offers) or loan_take (accept an offer), leaving routing to inference.

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