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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description usefully reinforces that it never writes and clarifies that with_risk attaches AML data and that it lists only existing on-chain counterparties, adding real context beyond the annotations.

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 tight sentences with the primary action front-loaded and the risk flag called out clearly. The 'Read-only... never writes anything' clause partially duplicates the annotations, costing a bit of economy.

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?

There is no output schema, so the description must carry the return-value burden; it discloses that counterparties carry AML score/risk level/sanctioned when with_risk is set. Combined with full parameter coverage, this is nearly complete, though return shape and pagination behavior remain unstated.

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 every parameter is already documented in the schema. The description restates the category and with_risk semantics (including examples and the leave-empty behavior) without adding syntax or format meaning 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?

The description states a specific verb and resource ('List the counterparties an address has transacted with') and scopes it with an optional category filter, so the purpose is unambiguous. It does not explicitly distinguish itself from siblings like screen_address or list_transactions, so it falls short of a 5.

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?

It hints at usage by explaining the optional category filter and the with_risk flag, giving the agent implied context for when each option applies. However, it names no alternatives and gives no when-not-to-use guidance relative to siblings such as screen_address.

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