email_domain_check

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

No annotations are provided, so the description carries the full burden. It discloses a cost of $0.001 USDC via x402 and the security/network category, but it does not describe the actual operation, whether it is read-only, what data it uses, or what the response looks like.

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 very short and contains no waste; the cost sentence is useful. However, it is under-specified and mostly repeats the tool name, making it less effective than a concise yet informative description.

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?

With no output schema, a generic params object, and no annotations, the description must provide substantial behavioral and usage context. It fails to explain input requirements, return values, or operational semantics, leaving the agent unable to invoke 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?

The schema has 100% coverage for its single generic 'params' property, but that property is only described as 'Tool parameters as JSON object'. The tool description adds no detail about expected fields (e.g., email or domain), so the baseline of 3 applies without additional value.

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 is essentially a restatement of the tool name ('email domain check') with a broad category ('Security & Network tool'). It does not specify what exactly is checked (e.g., MX records, DNS, blacklists) and does not differentiate it from sibling tools like validate_email, verify_email, or dns_lookup.

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?

No guidance is given on when to use this tool versus alternatives. There are no exclusions, prerequisites, or examples. The only contextual hint is the 'Security & Network' category, but this is too vague to direct an agent.

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