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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is clear. The description adds valuable behavioral context: the inclusion of sliding-scale rules for specific controls (3.5.3 and 3.13.11) and that passing sections returns additional views. This goes beyond annotation-provided information.

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 concise and front-loaded. The first sentence immediately states the core action and resource, followed by the key output details and the optional sections behavior. Every sentence adds value, with no redundant content.

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?

Without an output schema, the description appropriately explains what the tool returns (full requirement text, control family, SPRS point weight, sliding-scale rules, and optional objectives/crosswalk). It covers the essential behavior for effective use, though it does not address error handling or edge cases like invalid control numbers.

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?

The input schema has 100% coverage for both parameters, including descriptions for 'control' and 'sections.' The description reinforces this with examples ('3.5.3') and clarifies the 'sections' parameter's effect, but adds no fundamentally new semantic information beyond the schema—hence the baseline score of 3.

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 states the tool's function: 'Get one NIST SP 800-171 Rev 2 security requirement by number' with specific output components (requirement text, control family, SPRS weight). It distinguishes from siblings by covering combined lookups (objectives, crosswalk) and referencing Rev 2 while sibling lookup_rev3_requirement exists.

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 provides explicit usage guidance: 'Call this when the user asks what a specific 800-171 or CMMC Level 2 control requires or how many SPRS points it is worth.' It also hints at alternatives by saying 'instead of three' but does not name them, so it lacks explicit when-not-to-use or alternative tool names.

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