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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds useful context beyond those: the operation is evaluative, returns blocking violations and warnings, uses caller-supplied inputs, and is paid at $0.002 per call. There is no contradiction with the annotations, though it omits error/response details.

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?

The description is three sentences with no filler. The core behavior is front-loaded, followed by exclusions and pricing. Each sentence adds distinct operational information, making it appropriately concise and well-structured.

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 a nested rules object containing 500 possible items, the description should clarify return shape, rule semantics, and severity handling, but it does not. It also fails to explain how this engine differs from the sibling agent_procurement_policy_engine variants or procurement_policy_control. The description is adequate for a coarse understanding but not complete enough for confident correct invocation.

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, but it only restates that facts and rules are caller-supplied. It does not explain the shape of the facts object, how rule fields map to fact keys, how operators like 'exists' behave, what severity defaults to, or how value interacts with op. The schema's property names and enum provide minimal structure, but semantic guidance is missing.

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 opens with a specific verb and resource: it evaluates caller-supplied facts against caller-supplied rules and returns blocking violations and warnings. It also states an intended domain (agent procurement / fraud risk) and lists excluded domains. However, it does not distinguish this engine from its three identically named agent_procurement_policy_engine siblings, so it just misses full clarity.

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?

The description gives an explicit intended use ('agent procurement / fraud risk') and an explicit do-not-use list ('legal, identity, sanctions, fraud, contractual, or regulatory adjudication'). It also adds a practical cost condition. It does not name specific alternative sibling tools or explain when to choose one of the other policy engines, so it is not a 5.

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