nist-mcp

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

Annotations provide readOnlyHint=true and idempotentHint=true, indicating safe, repeatable operations. The description adds value by specifying the return content ('definition, authoritative source, and related terms'), which is not covered by annotations. It doesn't contradict annotations, as 'look up' aligns with read-only behavior.

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 front-loaded with the core purpose, followed by specific usage guidance and return details in just two sentences. Every sentence earns its place by adding critical information without redundancy, making it highly efficient 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?

Given the tool's moderate complexity, rich annotations (read-only, idempotent), 100% schema coverage, and the presence of an output schema, the description is complete. It covers purpose, usage, and return values adequately, with no gaps for the agent to operate effectively.

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 100%, so the schema already documents parameters well. The description adds meaningful context by explaining the semantic difference between 'term' (exact match) and 'query' (keyword search), which clarifies usage beyond the schema's technical descriptions. This compensates for the high baseline.

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 purpose with specific verbs ('Look up') and resources ('NIST cybersecurity/privacy terms'), distinguishing it from siblings by focusing on glossary terms rather than controls, documents, or databases. It specifies the domain (NIST cybersecurity/privacy) and the action (look up terms).

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 provides usage guidance: 'Use 'term' for exact match, 'query' for keyword search.' This directly tells the agent when to use each parameter, offering clear alternatives within the tool itself. It distinguishes from siblings by focusing on glossary terms rather than other NIST resources.

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