MailFerret

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

With no annotations and no output schema, the description carries the full behavioral burden. It usefully enumerates the derived signals (SPF, DMARC, catch-all, likely pattern), which hints at a read-only analysis, but says nothing about rate limits, permissions, latency, or whether results are cached/fresh.

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?

A single tight fragment with no filler, and the enumerated outputs are front-loaded. It is efficiently sized, though the missing verb makes it read as a label rather than a complete instruction.

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?

Without annotations or an output schema, the description partially compensates by listing what is returned, which is genuinely helpful. It still omits input format, sibling routing, and any behavioral constraints, leaving gaps for a tool whose structured metadata is entirely empty.

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?

One required parameter ('domain') with 0% schema description coverage. The phrase 'A company's email setup' loosely signals that the input is a company domain, but no format, apex-vs-subdomain, or normalization guidance is provided.

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 a noun phrase listing returned data (provider, catch-all, SaaS tools, DMARC, patterns) rather than a verb+resource statement of what the tool does. It implies domain-level email reconnaissance and is distinguishable from the email-specific siblings, but the agent must infer the action ('analyze/lookup a domain's email setup').

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 when-to-use guidance and no routing relative to siblings find_work_email and verify_email. The agent gets no explicit condition telling it to pick this over per-address tools, though the domain-scoped framing offers a weak implied use case.

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

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

With no annotations, the description carries the full burden, and it usefully discloses that it performs a live SMTP check and catch-all detection — which signals latency, possible greylisting/failure, and reduced reliability for catch-all domains. It omits what happens when no email is found, whether results are cached, and any rate-limit or auth expectations, so it is partial rather than complete.

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?

A single tight sentence with the resource front-loaded and the operational detail (live SMTP check, catch-all detection) parenthetically appended. Zero wasted words.

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 3-param tool with no output schema and no annotations, the description covers the input contract and one operational trait but says nothing about the return shape (email only? confidence score? null on failure?) or failure modes. An agent can invoke it, but cannot anticipate the response.

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; it merely restates the three field meanings (first name, last name, company domain) already obvious from the param names. It never specifies the domain format (bare 'example.com' vs URL) nor notes that last_name is optional while first_name and domain are required, leaving real format ambiguity unresolved.

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?

States a specific verb and resource ('Find a person's verified work email') plus the distinguishing output trait (verified). It doesn't mention the siblings verify_email or domain_email_intel, so an agent must infer why this differs from plain verification, but the core purpose is unambiguous.

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 the required inputs but never says when to choose this over verify_email or domain_email_intel, nor any prerequisite or exclusion. No usage guidance beyond the implicit 'you have a name and domain' condition.

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

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

With no annotations, the description carries the full burden. It usefully discloses the verification methods, including that a live SMTP RCPT probe is performed — a meaningful behavioral fact implying network activity, latency, and possible rate-limiting or blocked connections. However, it says nothing about cost, throttling, or what a 'catch-all' result implies for trustworthiness.

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?

A single front-loaded sentence: the operation and its scope lead, and the parenthetical method list is compact and information-dense. No 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 tool with no output schema, the definition covers what is checked but not what comes back (e.g. deliverable/undeliverable/risky catch-all classifications) nor any latency or failure caveats an agent would need to interpret results or set expectations.

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% for the single 'email' parameter, so the description would need to compensate, but it adds no format details (bare address vs. display name, normalization). The parameter is self-evident from the tool name, so the gap is mild rather than harmful.

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?

States a specific verb ('Check') and resource ('email address') plus the exact deliverability dimensions tested (MX, provider, catch-all, live SMTP RCPT). This clearly separates it from siblings like find_work_email (discovery) and domain_email_intel (domain-level), though it never names them explicitly.

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?

There is no guidance on when to use this versus domain_email_intel or find_work_email, nor any prerequisites (e.g. cost/latency of a live SMTP probe, bulk-verification caveats). Usage is only inferable from the name and the parenthetical method list.

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