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 names the data sources checked (USDT/USDC blacklists, sanctions across six EVM chains plus OFAC, scam DBs, community reports, behavioural patterns) and warns 'Costs credit', which is important for agent budgeting. It omits auth requirements and rate limits, so it falls short of a 5.

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 sentences, front-loaded with the return values, then the usage trigger, then the cost warning. Every sentence earns its place with no filler.

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 output schema and no annotations, the description must stand alone, and it communicates the return shape (allow/review/deny with named reasons) and the credit cost. Given the nested policy object and multiple risk sources, it covers the essentials, though the interaction between policy and default behaviour could be spelled out more.

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 schema already documents address, amount_usd, and the nested policy object including the conservative default. The description adds only a passing reference to 'your own risk policy' and no syntax or semantics beyond the schema, so the baseline 3 applies.

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+resource ('Return allow / review / deny for a counterparty address') and names the exact output vocabulary, which no sibling provides. An agent can tell this is the decisioning tool versus the screening siblings 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?

'Use this before every outbound transfer' gives a clear triggering context. However, it does not explicitly distinguish itself from onyx_screen, onyx_screen_batch, or onyx_preflight, so the agent must infer the routing.

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