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

With no annotations, the description carries the full burden of behavioral disclosure. It only lists features; it does not state side effects, network lookups, input expectations, or return behavior. The agent cannot infer whether this is a read-only local check or an external API call.

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 extremely short and front-loaded with the 'Email Intel' label, so it is concise. However, it is more of a tagline than a structured description; there is no breakdown of input, output, or usage context, so the conciseness comes at the cost of necessary 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 tool with one parameter and no annotations, the description is incomplete. It does not state what the 'q' parameter should contain, whether an email or domain format is expected, or what kind of output to expect. The presence of an output schema does not excuse the lack of input semantics.

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 describes one parameter 'q' with zero description coverage, and the tool description never explicitly defines 'q' as an email address or any other value. The feature list (Gravatar/MX/disposable) strongly implies 'q' is an email, but the description fails to compensate for the schema's lack of documentation.

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 labels the tool as 'Email Intel' and lists three specific capabilities (Gravatar, MX, disposable detection), which hints at the tool's scope. However, it lacks a clear verb and resource (it doesn't say 'look up' or 'retrieve'), so the exact action and object remain vague.

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 no guidance on when to use this tool versus the many email-related siblings (emailrep, emailsec, emailformat, hibp_email, etc.). The feature list implies use cases, but there is no explicit 'use for X' or mention of alternatives.

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