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

No annotations are provided, so the description carries the behavioral burden. It discloses that unknown rule numbers are refused with known ones listed, that input is case-insensitive, and that the response contains the rule text as written plus file URL. This is meaningful behavioral detail, though it does not discuss permissions or side effects, which are less relevant for a read-style tool.

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?

Three compact sentences with no filler. The core purpose is front-loaded, the parameter guidance is precise, and the error behavior earns its place. Every sentence adds useful information.

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 single-parameter lookup tool with an output schema present, the description is complete. It supplies the argument source, case handling, error behavior, and return fields. Nothing needed to call this tool safely and effectively is missing.

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 100%, so the baseline is 3. The description adds value beyond the schema by noting case-insensitivity, the validation/refusal behavior, and the explicit linkage to list_rules as the source of valid rule numbers. These extras help an agent invoke the tool correctly.

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 clearly identifies the tool as returning one rule as written, with a single resource type and the exact return fields. It is readily distinguishable from sibling list_rules, describe_schema, and describe_relations. The reference to 'from list_rules' anchors the argument source without ambiguity.

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 explains the required input, that it must be a rule number from list_rules, and that values are case-insensitive. It also describes the refusal behavior for unknown numbers. It does not explicitly name alternative tools or when-not-to-use conditions, but the list_rules prerequisite provides clear usage context.

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