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

No annotations are provided, so the description carries the full behavioral burden. It usefully discloses that no key is required and that the tool uses Wayback CDX and search links, but it does not mention rate limits, output behavior, pagination, or limitations.

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 a single, front-loaded sentence with useful specifics. The leading 'Paste Email Search:' label is slightly redundant with the tool name, but the rest is efficient and free of filler.

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 one-parameter lookup tool, the description is minimally adequate: it states the purpose, mechanism, and authentication requirement. However, q semantics are left implicit, and no usage example is provided. An output schema exists, so return-value details are not required here.

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 0%, so the description must compensate for the undocumented q parameter. It does not explicitly define q or provide a format/example, leaving the agent to infer that q is the email address to search for.

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 states a specific verb ('Find'), a specific resource ('email in public pastes'), and the mechanism ('Wayback CDX + search links'). This clearly differentiates it from siblings like paste_domain, which is domain-focused.

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 implies usage: search for an email address in public pastes. However, it gives no explicit guidance on when to prefer this tool over alternatives, nor any exclusions or prerequisites beyond 'no key'.

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