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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely non-obvious behavior: offers are advertisements rather than a matched book, nothing self-executes, and the best bid can sit at or above the best ask. That last point is valuable anti-misinterpretation context, though it stops short of describing pagination, depth limits, or staleness of the 'live' data.

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 the field inventory, then the crucial caveat about unmatched advertisements. Every sentence carries information; nothing is padded or repeated from the annotations.

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 no input parameters and no output schema, the description must carry the return-shape burden and does: it enumerates cumulative depth, offer count, payment methods, and the reversible flag per price level. Combined with the crossed-book caveat, an agent has enough to call it and interpret results correctly.

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 there is nothing for the description to disambiguate and the baseline applies. The description correctly spends no space on argument semantics.

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?

Names the specific resource (the live Haveno XMR/USD order book), its scope (both sides), and its pricing basis (centralized spot). Explicitly defines what `asks` and `bids` mean in maker terms, which lets an agent distinguish this from siblings like haveno_premium or haveno_payment_methods without opening a 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?

Usage is implied (fetch this when you need current order-book depth), but the description never states when to call this versus haveno_premium or haveno_payment_methods. It also doesn't say whether the book is a snapshot or streaming, leaving an agent to infer freshness from 'live'.

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