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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is fully covered. The description adds useful scope by stating what data is retrieved, but does not disclose auth needs, rate limits, or error behavior beyond what annotations provide.

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 short sentence with no wasted words, and the key information is front-loaded. However, it is a grammatical fragment rather than a complete sentence, which slightly reduces structural clarity.

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 a complete input schema, rich annotations, and an output schema, the description only needs to establish purpose and scope. It does that adequately for a simple lookup tool, though it could better situate itself among the related sibling tools.

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 100%, so the hostname and response_format parameters are already well documented by the input schema. The description adds no additional meaning about parameter usage or formatting, so the baseline score of 3 is appropriate.

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 identifies the resource (one hostname's certificate history) and the data returned: first/last issuance, count, and issuers. It is more specific than a tautology, but lacks an explicit verb and does not distinguish itself from sibling tools like subdomain_timeline or watch_domains.

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 offers no when-to-use guidance, no exclusions, and no mention of alternatives among the sibling tools. An agent must infer the appropriate context solely from the stated purpose.

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?

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds value by revealing the ranking heuristic and that results are scoped to a look-back window, but it says nothing about cost, rate limits, or result ordering guarantees.

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 that puts the returned entity first and the ranking factors after. Dense but every clause carries information; 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?

An output schema exists, so return-value structure need not be explained, and the ranking logic is described. However, for a heuristic/analytical tool with four siblings in the same domain-history space, the definition omits any routing guidance or caveats about false positives, leaving a gap in how to deploy it.

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 75% – days, domain and response_format are documented in the schema, only 'top' lacks a description. The description gestures at the time window ('in the window') but adds no format, default, or constraint detail beyond the schema, so the baseline 3 applies.

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 gives a specific verb-like result ('product-like names that first appeared under a domain') and enumerates the ranking signals (newness, several hostnames, staging/beta/preview variants, product words), so an agent knows what comes back. It does not distinguish this from siblings like new_subdomains or subdomain_timeline, which return adjacent data, so it stops short of a 5.

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 explicit when-to-use statement, no exclusions, and no mention of the sibling tools that cover overlapping data (new_subdomains, subdomain_timeline, hostname_history). The use case can be inferred from 'upcoming launch' but the agent is left to guess when this beats the alternatives.

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?

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so safety is covered. The description adds valuable behavioral context beyond annotations: the ordering (newest first), the data provenance (first certificate appearance in the window), and the enrichment fields (product-like name and environment words).

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 efficient sentence with no wasted words. The front-loaded phrase 'Raw evidence' is somewhat vague, but the sentence remains compact and informative.

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 output schema and annotations, the description need not explain return values or safety. However, the tool has four closely related siblings and the description provides no routing guidance, which is a meaningful contextual gap for selection among subdomain-related tools.

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 80%, which is high, so the baseline is 3 even though the description adds no parameter semantics. The description does not explain domain, days, limit, response_format, or include_infrastructure, but the schema already documents most of these.

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 resource and filtering criterion: hostnames whose first certificate appeared in the given window, ordered newest first. It does not explicitly differentiate this from sibling tools like subdomain_timeline or hostname_history, and it lacks an action verb, so it falls short of a perfect 5.

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 offers no guidance on when to use this tool versus alternatives. It does not mention the sibling tools or the conditions under which raw new-subdomain evidence is preferred over a timeline or history view.

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?

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is fully covered. The description adds interpretive framing about what bursts mean, but says nothing about downstream behavior (resolution, whether empty months appear, data sources). Modest added value against rich 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 short sentences, front-loaded with what the tool returns. The second sentence is interpretive rather than structural but still earns its place as usage framing. 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?

An output schema exists, so return-shape explanation is not required, and annotations carry the safety profile. However the underexplained 'months' parameter and the lack of any differentiation from the overlapping sibling tools leave an agent with real gaps when choosing between them.

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?

At 67% schema description coverage, the description is expected to compensate for gaps. The 'months' parameter has no schema description and the description never mentions it; response_format is likewise untouched. Only 'domain' is well documented, and that comes from the schema itself, not the description.

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 names a specific resource and scope: 'New hostnames per month and the product-like names that first appeared each month.' An agent can tell it produces a time-bucketed subdomain inventory. It does not differentiate itself from siblings like new_subdomains or hostname_history, so it stops short of a 5.

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?

'Bursts often line up with launches, rebrands or new regions' implies the tool is for detecting launch/rebrand activity, which is useful context. But there is no explicit when-to-use statement, no prerequisites, and no routing to the sibling tools that overlap in this space.

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?

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds that results are scoped to a time window and combine two signal types, but says nothing about rate limits, cost, or data limitations that would matter for a multi-domain sweep.

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 with no filler, and the competitor-scope constraint leads. It is a fragment rather than a full clause ('A radar over...'), which is slightly terse but not wasteful.

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?

An output schema exists, so return values needn't be spelled out, and annotations carry the safety profile. Still, for a tool that merges two signal sources across multiple domains, one sentence leaves gaps around result granularity and how the two signal types interact.

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 100%, so 'days', 'domains' (with the 2-8 bound), and 'response_format' are already fully documented in the schema. The description restates the 2-8 competitor limit and the window concept but adds no syntax or format detail beyond the schema, making the baseline 3 correct.

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 names a concrete capability (monitoring new hostnames across 2-8 competitor domains) and the payload it returns ('top launch signals'). It's clear what the tool does but never distinguishes itself from siblings like new_subdomains or launch_signals, which appear to cover overlapping ground.

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?

Usage is only implied: the '2-8 competitors' and 'window' framing suggests a competitive-monitoring scenario, but there is no explicit when-to-use, when-not-to-use, or pointer to an alternative sibling. An agent must infer the choice from names alone.

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