Cheapest Domains

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

Adds substantial behavior beyond the annotations: Cloudflare-first with configured fallback ordering, a short-circuit on taken names, nullable premium semantics ('null premium is unconfirmed, not standard tier'), and the evidence TTL of 5 minutes / 30 days for taken names. None of this is derivable from the schema or the hint flags.

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?

Purpose is front-loaded in the first sentence and every following clause carries real information (fallback order, null semantics, TTL, exclusions). It is dense with semicolons and slightly harder to scan than it needs to be, but there is 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?

There is no output schema, yet the description covers the return surface itself: separate availability facts, nullable premium, provider attempts, and check times. Combined with the recheck/expiry guidance and the explicit scope exclusions, nothing an agent needs to call this correctly is missing.

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 schema already documents all four parameters in detail, including the fresh/pending-claims/cooldown behavior. The description corroborates 'optional selected registrar' and recheck timing but adds no new syntax or format detail, 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?

States a specific verb and resource with scope: 'Check one exact domain.' The word 'one' and the paired sibling check_availability_batch make the single-vs-bulk distinction immediately legible, and 'exact' signals no fuzzy matching.

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?

Gives concrete conditions: fallbacks run 'only for missing facts', 'a taken name ends the chain', recheck after expiresAt, and fresh only 'when the user asks'. The closing 'No prices, purchase or reservation' implicitly routes price/purchase intent elsewhere, but no sibling is named explicitly, so it stops short of a 5.

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?

Goes well beyond the annotations by disclosing early enrichment termination (premium may stay null), partial-failure semantics (answers received plus retry guidance, no automatic retries), and that cachedOnly performs no provider calls — behavior an agent cannot infer from readOnlyHint=false / openWorldHint=true alone. This explains why the call is not read-only or idempotent: it hits external providers and can partially fail.

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?

Five tight sentences, each carrying distinct information (scope, enrichment cutoff, failure behavior, cache mode, out-of-scope features) with the core capability front-loaded. No filler or restatement of the title.

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-parameter tool with no output schema, the description covers the ambiguous outcome cases that matter most: null premiums, partial results with retry guidance, and cache-miss behavior. It stops short of describing the shape of a per-extension result, which is a minor gap given no output schema exists.

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 coverage is already 100%, so the baseline is 3, but the description adds real meaning for cachedOnly ('makes no provider calls', cache misses stay unconfirmed) and restates the 20-extension cap on tlds. It does not add anything for the name parameter beyond the schema's own explanation.

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), resource (one name's availability), and explicit scope (up to 20 extensions, reusing shared evidence), which implicitly separates it from the single-extension check_availability sibling. The closing negative scope ('No selected-registrar fallback, fresh mode, prices or purchases') further fences it off from get_registrar_link/get_tld_prices/estimate_cost.

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?

Gives clear when-not guidance — no registrar fallback, no fresh mode, no prices or purchases — which steers the agent to the price and purchase siblings. It also explains that cachedOnly is the zero-provider-call mode. What it lacks is any explicit 'use this instead of check_availability when you need >1 extension' routing statement.

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 annotations already covering safety (readOnlyHint=false, destructiveHint=false), the description adds rich behavioral context: it uses saved/cached evidence, makes no new availability requests, treats cache misses as 'Not confirmed', and returns standard offers, premium facts, dates and links. It does not detail idempotency or openWorldHint, but those are already annotated.

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?

Dense but tightly packed with useful constraints, front-loaded with sequencing and scope. Some sentences pack multiple ideas ('Returns standard reference offers, premium facts, dates and links.'), but nothing is wasted.

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 read-only comparison tool with no output schema and 100% schema coverage, the description covers prerequisites, pricing basis, cache behavior, return shape, and result-size limits. It leaves minor unknowns (exact ordering of comparison) but is otherwise sufficient to call 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?

Schema coverage is 100%, so the baseline is 3. The description reinforces the 10-domain cap and price orientation but adds no syntax or format details beyond the schema's own description of comma/whitespace separation and renewal cents.

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 and resource ('compare up to 10 candidates') and explicitly distinguishes itself from siblings ('After checking exact names with the availability tools', 'Does not generate names', 'No new availability requests'). An agent can tell it apart from check_availability and get_naming_guidance without opening schemas.

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?

It gives explicit sequencing ('After checking exact names'), bounded scope ('up to 10 candidates', 'Split larger lists into bounded groups'), and what not to expect ('Does not generate names'). This is near-complete routing and boundary guidance.

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 declare the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true, idempotentHint=false), so the description need not restate it. The description adds a real behavioral detail not present anywhere else: it returns null for unknown multi-year term totals, which matters since there is no output schema.

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?

Three short sentences, front-loaded with the core purpose, then the null-return caveat, then the exclusion. No padding or restatement of the title.

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 read-style estimation tool with full schema coverage and no output schema, the description covers purpose, scope, exclusions, and the null edge case. It could say more about what the estimate includes (currency, breakdown by year), but nothing essential for invocation is missing.

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 every parameter is already documented in the schema. The description adds only the general framing of 'one TLD at a registrar' and does not supplement the years, name, or registrar semantics, so 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?

States a specific verb and resource with scope: 'Estimate new registration plus subsequent renewals for one TLD at a registrar.' It explicitly carves out what it is not ('Not a transfer or existing-domain renewal quote'), which separates it from pricing/link siblings.

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?

It gives clear when-not guidance for transfer and existing-domain renewal scenarios, which is genuinely useful routing information. It stops short of naming a specific alternative tool (e.g., get_tld_prices or search_prices), so the agent must infer the counterpart itself.

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?

The description adds real behavioral value beyond the annotations: it names the data source (Cloudflare Radar), the return shape (exact top-100 rank or popularity group, categories, locations, data dates, CC BY-NC 4.0 attribution), and an important caveat that missing data is not zero competition. However, there is tension with annotations that declare readOnlyHint=false and idempotentHint=false for what the description frames as a pure lookup; the description does not address why a read-style query is flagged non-read-only or non-idempotent, leaving a gap that a caller would want resolved.

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?

Four short sentences, front-loaded with the core action, then return shape, then exclusions, then the key caveat. No sentence is redundant and nothing is buried.

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 and only two parameters, the description carries the load well: it explains what is returned, the data provenance, licensing attribution, and the interpretation caveat about missing data. An agent has enough to call it and interpret results 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?

Schema description coverage is 100%, so name and tld are already documented, including the note that the exact domain is sent to providers. The description adds no parameter-level detail of its own (e.g., no coverage of ranking scope per location), so baseline 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?

States a specific verb and resource: 'Look up one exact domain in Cloudflare Radar's global DNS popularity ranking.' It also distinguishes itself from sibling concerns by ruling out SEO difficulty, name competition, and availability, so an agent can separate it from check_availability and get_naming_guidance without opening schemas.

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?

Gives clear context ('one exact domain') and explicit exclusions ('Not Google SEO difficulty, name competition, or availability'), which steers the agent away from siblings. It stops short of naming a preferred alternative or stating prerequisites, so it is clear but not fully routing.

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?

The description usefully discloses that this is a static reference with no name generation or availability checking, which is exactly the kind of context a getter needs. However, the annotations declare readOnlyHint=false and idempotentHint=false for what the text describes as a pure static lookup; the description neither acknowledges nor reconciles that mismatch, leaving the side-effect profile ambiguous.

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, zero filler. The content list is front-loaded and the scope limitation follows immediately, so an agent can decide in one read.

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 parameters, no output schema, and low complexity, the description covers what the tool returns at a conceptual level (criteria, guidance, definitions). It could say slightly more about the form of the returned reference material, but nothing essential for correct invocation is missing.

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 tool takes zero parameters, so the baseline is 4. There are no parameter semantics to explain, and the description correctly says nothing about inputs.

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 (Return) and enumerates the exact resources: naming criteria, renewal-price comparison guidance, and availability-status definitions. It also draws a clear boundary against siblings by stating it does not generate names or check availability, which separates it from check_availability and the price/registrar tools.

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 sentence 'does not generate names or check availability' gives a clear negative-use signal and implicitly routes the agent to check_availability/estimate_cost, but it never names a specific alternative tool or states the positive condition under which this reference should be consulted.

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?

Beyond the annotations, the description discloses data provenance (scheduled refreshes vs. the registrar's own price page archived by the Internet Archive) and two caveats: 'A first record may be older than its date' and 'Availability is not checked.' That is meaningful behavioral context for interpreting results. Note the readOnlyHint=false annotation is odd for what reads as a retrieval tool, but the description never asserts read-only status, so it does not directly contradict it.

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 core purpose is front-loaded in the first clause, followed by return-field detail and two short caveats; every sentence carries information. The opening sentence is dense and long, but it is not padded or repetitive.

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, the description carries the burden of explaining return values, and it does so — price periods, first-seen/last-seen dates, and the source flag — plus caveats about record dating and skipped availability checks. What it lacks is any sense of result ordering or scale, which keeps it from a 5.

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%, with tld, price, format and registrar all documented in the schema (including enums and defaults), so the baseline is 3. The description adds no parameter-level syntax or constraints beyond what the schema already supplies.

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 — return how each covered registrar's renewal/registration price for one extension changed over time — with a clear temporal framing that separates it from current-price siblings like get_tld_prices and search_prices. It does not name those siblings explicitly, so it falls 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?

Usage is implied by the temporal focus and the boundary note 'Availability is not checked,' which steers the agent away from availability checks. However, there is no explicit when-to-use/when-not guidance nor any named alternative (e.g. get_tld_prices for current prices), so routing is left to inference.

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 declare destructiveHint=false and openWorldHint=true; the description adds the meaningful behavioral facts the annotations don't carry: no navigation, no availability check, no purchase, and that two registrars return a copy/paste fallback rather than a direct link. The readOnlyHint=false declaration is slightly at odds with the side-effect-free framing, though it is defensible for an open-world link builder, so this is worth noting but not a hard contradiction.

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?

Three short sentences, zero filler, with the core purpose stated first and the constraints and caveat following. Every clause earns its place.

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-required-param link builder with no output schema, the description covers purpose, boundaries, and the registrar-specific fallback behavior. It stops short of saying what the constructed result actually looks like (URL vs. copy/paste text structure) or how the caller should use it, which is a minor residual gap.

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 each parameter (tld, name, registrar) is already documented with patterns and semantics, including "omit to compare all" for registrar. The description references "name and extension" but adds no format, aliasing, or defaulting detail beyond the schema. Baseline 3 is 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?

Specific verb ("Construct") plus specific resource ("verified registrar search destination") scoped to a proposed name and extension. The negative clauses ("Does not navigate, check availability, or purchase") cleanly separate it from check_availability, get_domain_popularity, and any purchase flow, so an agent can pick it apart from siblings without reading schemas.

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?

Explicit exclusions establish when this tool is wrong (not for availability checks or purchasing), which implicitly routes the agent to check_availability / search_prices. It also names a context-specific edge case (NameBright and AWS Route 53 use a copy/paste fallback). No explicit positive "use this when..." trigger or named alternative, which keeps it from a 5.

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 declare readOnlyHint=false, openWorldHint=true and idempotentHint=false, so the agent already knows this is a network-touching, non-idempotent operation. The description's 'Get' framing reads as a passive retrieval and it never explains what 'connected', 'fresh counts', or 'registrars not compared' mean operationally (does it trigger a fresh comparison? which registrars?). With annotations carrying the safety/state profile, this adds little beyond a data-field list.

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 or repetition. It is slightly list-heavy, reading as a field inventory rather than a crisp purpose, but it wastes no 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?

With no output schema, the description does enumerate the returned data (coverage, timestamps, fresh counts, failures, not-compared registrars), which is genuinely useful. However, it does not explain how to interpret those fields, what 'fresh' implies about state changes, or the network/auth implications of an openWorldHint tool, so it is only partially complete.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline for a parameterless schema 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 definition gives a verb and resource ('Get ... registrar coverage'), which is better than a tautology, but 'coverage' is undefined jargon and the rest of the sentence is a list of returned data fields rather than a purpose statement. It does nothing to distinguish the tool from siblings like get_tld_prices or get_domain_popularity.

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 when-to-use, when-not-to-use, or alternative-tool guidance. An agent cannot tell from this description when registrar coverage is the right thing to fetch versus any of the eight sibling lookup tools.

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?

Beyond the annotations (readOnlyHint=false, openWorldHint=true, non-idempotent), the description discloses concrete output characteristics: source failures, quote timestamps and minimum terms, plus the availability gap. This tells the agent what data quality caveats to expect, which annotations alone cannot convey.

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 dense sentences with zero filler: the scope statement comes first and the return/caveat information second. Nothing is redundant with the title or schema.

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, the description usefully names key return elements (source failures, quote timestamps, minimum terms) and the availability limitation. Pagination and formatting behavior are left entirely to the schema, but for a 13-param read tool this is largely sufficient.

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?

All 13 parameters have 100% schema description coverage, including enums, defaults, ranges and even cross-parameter notes (favorites, includeStale), so the schema carries the burden. The description adds no parameter-level meaning, which is the correct baseline when coverage is this high.

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 (compare) and scoped resource (all covered registrars for one extension), which implicitly separates it from the name-driven search_prices sibling. It does not explicitly name that sibling, so the differentiation is inferred rather than stated.

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?

'availability is not checked' is a useful boundary cue that implies check_availability should be used instead, but no alternative is named and no other when-to-use context (e.g. vs search_prices or estimate_cost) is given. Usage is only implied.

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 openWorldHint=true, non-readOnly, non-idempotent, non-destructive. The description adds genuinely useful context beyond them: no generation or registrar checks occur on open, no subscription connection, and no model API key required. It stops short of describing the return payload shape.

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?

Three tight sentences, front-loaded with the action and followed by the data collected and the non-effects. 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?

No output schema exists, yet the description covers the invocation effect, the collection step, and the boundary conditions (no key, no subscription, no checks). Minor gap is the exact nature/contents of the 'text workflow' return, but overall it is adequate for a no-param opener.

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?

With zero schema parameters, the baseline is 4. The description helpfully enumerates what the form will collect (seed names, optional project brief, count, annual renewal budget), which compensates for the empty schema by telling the agent what inputs will be solicited.

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 action (open the naming form / return its text workflow) on a specific resource, and distinguishes itself from the sibling research tools by noting that the assistant uses those tools to generate and check ideas. 'Text workflow' is somewhat vague about what that artifact actually is, keeping it out of 5 territory.

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?

It establishes context clearly, pointing to the research tools for generation and registrar checks and stating what opening does NOT do. It stops short of explicitly naming when to choose this over get_naming_guidance, so the alternative routing is implied rather than enumerated.

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 cover safety/open-world posture but leave behavior vague (readOnlyHint=false on a search tool is unexplained). The description fills that gap usefully: it discloses that saved offers persist after a failed refresh with stale flags and source timestamps, that results carry citations, coverage and pagination, and that Cloudflare samples are explicitly labeled. That is real behavioral context beyond the structured fields.

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?

Four sentences, front-loaded with the core compare action before the staleness and return-value details. Dense but no filler; the scoping exclusion is placed last, which is slightly buried but acceptable.

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 17-parameter search tool with no output schema, the description covers return shape (prices, citations, timestamps, coverage, pagination), default ordering, and stale-data behavior. Since the schema fully documents parameters, the remaining burden is small; a little more on when to prefer this over sibling price tools would make it complete.

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 schema already documents all 17 parameters in detail, making 3 the baseline. The description adds only the default sort context ('annual renewal by default') and the labeling of Cloudflare samples, contributing little beyond what the schema provides.

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+resource: compare standard renewal prices across domain extensions and registrar offers, sorted by annual renewal. It also carves out scope with 'Does not check exact-name availability,' which separates it from the check_availability siblings. It stops short of distinguishing itself from price-adjacent siblings like get_tld_prices or estimate_cost, so it lands at 4 rather than 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?

Usage context is implied ('Find affordable domain extensions and registrar offers') and one exclusion is given ('Does not check exact-name availability'). However, no alternative tool is named and no explicit when-to-prefer rule is stated, so the agent must infer routing from sibling names alone.

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