Own It

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

Annotations already cover readOnly, openWorld, idempotent and non-destructive, and the description layers on materially new behavior: a 24-hour cache, the explicit limitation that it cannot see inside accounts (so Google Business Profile or tag ownership is reported as a check, never guessed), and a plain-words statement of what the response contains. That is exactly the kind of beyond-annotations context that prevents misreading results.

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 opening clause front-loads the core purpose, then the sentence chain expands into detail rather than burying the point. It is dense and list-heavy (ten-plus platform names, many tag types), but those enumerations serve to tell the agent which signals are detectable. Slightly overgrown, but nothing is 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?

With no output schema, the description carries the return contract itself: per-layer controller, portability rating, plain-words reason, evidence, sources, suggested first step, plus a 0-100 portability score. Combined with the stated accuracy boundary and the cache TTL, an agent has everything needed to call it and interpret the result.

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 all three parameters are already documented in the schema, including that profile_urls are classified not fetched and business_name is compared against the public registrant. The description restates the Google Business Profile / profile-links role but adds no format, limit or semantics beyond the schema. 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?

The description gives a precise verb and scope: mapping who controls each layer of a business's web presence and how portable each layer is, all from public data. It enumerates the layers and data sources (RDAP, DNS, MX/SPF, page fingerprints), so an agent knows exactly what work the tool does. It does not, however, explicitly differentiate itself from siblings check_domain_control or list_fingerprints, 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 rather than stated: an agent can infer this is the broad multi-layer audit, but the description never says when to prefer it over check_domain_control or list_fingerprints. It does add a boundary condition ('from public data only') and clarifies that profile links are classified, not fetched, which nudges toward correct invocation. No explicit when-not or alternative 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?

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds genuinely useful behavior beyond that: a 24-hour shared cache with audit_ownership, a 0-100 control score, per-layer reasons plus 'first step to take control,' and raw registration facts. It does not mention rate limits or failure modes, but adds solid context.

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?

Front-loaded with the verb and the fact inventory, then the return shape and cache note. The long enumeration costs some density, but each clause names a distinct deliverable and nothing is redundant padding.

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 annotations covering safety, the description carries the return-value burden and does so by specifying the score, per-layer reasons, action step, and raw facts. What it lacks is guidance on interpretation thresholds or how the score is derived, which an agent scoring control would find useful.

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% and both parameters are documented in the schema, so the baseline is 3. The description adds only an indirect hint that registrant data may be compared (relevant to business_name) and nothing about domain format beyond what the schema already says.

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 enumerates the exact resources and facts covered: registrar/IANA id, registrant, EPP status, dates, DNSSEC, nameservers, mail provider from MX/SPF. This is far beyond a tautology. It only partially differentiates from audit_ownership, mentioning it solely as a cache sharer rather than as a distinct alternative.

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 via 'without reading the website,' suggesting this is for situations where crawling is unwanted, and the shared-cache note hints at a relationship with audit_ownership. However, there is no explicit when-to-use/when-not-to-use statement or rule for choosing between this and audit_ownership.

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, false destructiveHint and closed-world (openWorldHint=false). The description adds genuinely new context: it is a 'static reference, no network access', and the response shape differs based on whether kind is supplied (counts per kind vs. full rule detail).

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 kind enumeration is long but front-loaded and informative rather than filler, and the two trailing clauses (counts without kind, static/no-network) carry real operational weight. Slightly dense for a single-parameter read tool, 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 one-optional-parameter, read-only reference tool with no output schema, the description covers the domain, the enum categories, the conditional return shape, and the no-network nature. Only a pointer to how the returned markers/portability ratings should be consumed is absent.

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% and the enum values are already documented, so the baseline would be 3. The description goes further by explaining the result-set behavior when kind is omitted, adding meaning the schema does not carry.

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 ('List the rules Own It uses to name vendors') and enumerates the concrete rule categories covered, so the agent knows exactly what is returned. It does not reference the sibling tools (audit_ownership, check_domain_control), but their scopes are distinct enough that confusion is unlikely.

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 gives a usage condition for the parameter ('Without kind it returns counts per kind'), which helps the agent choose between a summary and a filtered call. However, it never says when to reach for this tool versus the sibling ownership/control tools, so alternative selection 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.