dno_check

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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds valuable behavioral context: DNO list semantics, prefix matching details (3/6/7/10 digits), and what a match signifies. No contradictions with annotations.

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?

Two concise sentences with no extraneous information. The description is front-loaded with the core purpose and efficiently explains the DNO concept, use case, and matching behavior.

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 simplicity (one parameter, no output schema, clear annotations), the description covers the essential context: what DNO is, why it matters, and matching behavior. It does not specify return format, but that is not critical for a boolean-like check.

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% with a single parameter and clear pattern. The description adds prefix matching information, but this contradicts the schema's exact 10-digit requirement. This inconsistency reduces the helpfulness for an AI agent.

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 checks a phone number against the DNO list, explains what DNO is and why it's used (prevent caller ID spoofing), and distinguishes it from sibling tools like cnam_lookup or lrn_lookup by specifying the unique context.

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 implicitly guides when to use (when verifying caller ID authenticity) and explains the implication of a match (potential spoofing). It lacks explicit alternatives or when-not conditions, but the context is clear enough for an AI agent.

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