evaluate_rule

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

Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context: 'unknown premises stop the computation' and 'Bounded procurement amount tests from dated registry'. This goes beyond the annotations by explaining the closed-world behavior and the bounded scope. It doesn't describe output format, but with no output schema and a read-only evaluation tool, the key behavioral traits are disclosed.

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 dense and front-loaded: the first sentence states the core behavior, then the required facts and exclusions follow. Every sentence earns its place. It is slightly long but each line adds necessary constraint information. The structure is logical: behavior, valid IDs, required facts, exclusions.

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 read-only evaluation tool with no output schema, the description covers the input contract thoroughly: valid rule_ids, required facts, date format, and exclusions. It doesn't describe the return value or error behavior, but given the annotations cover safety and the input contract is well-specified, this is nearly complete. The main gap is what the evaluation result looks like, but that is not required for selecting and invoking the tool correctly.

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. It does: it explains rule_id values, required facts, amount as decimal string, tax_basis=HT, currency=EUR, scope, trigger, and trigger_date format. It also clarifies that as_of_date must match trigger_date. This is substantial parameter-level meaning beyond the bare schema. It doesn't document every possible fact key, but it covers the required ones.

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 ('evaluate') and resource ('rule'), and immediately clarifies scope: 'Bounded procurement amount tests from dated registry'. It also names the two valid rule_id values and the required facts, which distinguishes it from sibling tools like search, fetch, or compare_versions. This is a clear, specific purpose statement.

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 explicitly lists required facts, valid rule_id values, and the date format, and it states what the tool does NOT do ('No tax conversion, procedure choice, purchase authorization or general deadline computation'). This gives an agent clear when-to-use and when-not-to-use guidance, and implicitly distinguishes it from sibling tools that might handle those excluded computations.

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