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

Annotations only cover the read-only/no-destruction safety profile; the description adds the operationally critical traits: exact return surface (possible_match, lists_checked, list_dates, list_note, never an entry), rate limits per caller and per IP, quota sharing with the REST endpoint, and zero cost. This is exactly the value-add structured fields don't carry.

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 purpose and the differentiating constraint, and every sentence carries information. The Args block restates two fields but is justified because the schema has no descriptions; formatting is slightly loose (indented block, mixed line breaks) rather than 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?

With an output schema present, the description need not detail return values, yet it still defines the return scope and its limits. Quota, cost, alternative tool, and both parameter semantics are covered — everything needed to invoke this correctly and know when not to.

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 titles are bare, so the description carries the full burden. It defines name as a company or person name and, crucially, explains that country is an ISO 3166-1 alpha-2 code that only orders matches and never excludes one — a non-obvious behavior no schema field conveys.

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 and resource (a free yes/no sanctions 'preview' screener) and names the exact lists consulted (OFAC SDN, EU, UN). It also distinguishes itself from the sibling sanctions_screen by declaring it 'never' returns an entry, so an agent can separate the two 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?

Explicitly routes the agent: if matched entries are needed, use sanctions_screen, and it flags cost ($0) and quota (10/caller/day, 50/IP for key holders, shared with the POST endpoint). What's missing is a crisp 'use this when you only need a yes/no decision, before paying for a full screen' rule, but the context is clear enough.

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