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

With no annotations, the description carries the full burden and does much of it: it discloses the scoring range and direction, that name matching is conditional, and an unusual credit-cost model (3 credits resolved for Ghana mobile money, 1 for fallback, 0 if unresolved). It still omits auth/permission requirements and any statement about side effects, so it is not fully transparent.

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 sentences, front-loaded with the score range and polarity — the single most useful fact — before the optional enrichment. The credit-cost clause is dense but earns its place because pricing behavior is otherwise undiscoverable. Minor verbosity in the parenthetical cost breakdown.

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 seven-parameter tool with no annotations and no output schema, the description covers scoring semantics, the cost model, and most inputs. Gaps remain: default_country is unexplained, it never says whether at least one identifier must be supplied, and nothing beyond the 0-100 number describes the response.

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 0%, so the description must compensate, and it largely does: it explains the roles of ip, email, phone, name (folds in a name match) and momo_number/momo_network (Ghana mobile money, cost-bearing). The seventh parameter, default_country, is never mentioned and no expected formats are given.

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 ('One fraud score ... for a sign-up, order or lead') and even defines the output scale and polarity ('0-100, higher = riskier'). It covers the identifier universe (email, phone, IP, name, mobile money), which is enough for an agent to separate it from single-signal siblings, but it never explicitly names a sibling it is not, so differentiation is only implicit.

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 rather than stated: any of email/phone/IP can be supplied, and name plus mobile money is an optional enrichment. There is no explicit when-to-use versus validate_email/validate_phone/match_name, nor any statement of prerequisites (e.g. whether at least one identifier is required, despite 0 required parameters).

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