SHA-256, input discarded

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

The only behavioral disclosure is 'Page content is not stored,' a useful privacy guarantee. Since no annotations are provided, the description carries the full burden, yet it omits whether the URL is fetched, redirect handling, timeouts or rate limits, and why json/zone inputs are accepted.

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, front-loaded sentences with no filler; the primary output is stated first and the privacy note follows. Brevity is achieved by omitting parameter-level detail, but the structure itself is clean and easy to scan.

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 4-parameter, 0-required tool with no annotations and no output schema, the description covers only URL-derived behavior and leaves host, json, and zone entirely unexplained. Return values are stated, but error conditions, output shape, and how the tool relates to its 'citation' name are all 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 baseline of 3 applies; the schema already documents every parameter. The description adds only an implicit mapping from url to host/scheme/status and contributes nothing about host, json, or zone beyond what the schema states.

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 concrete output ('host, scheme, and HTTP status for a URL') with a specific verb and resource, so it is not a tautology. However, it conflicts with the tool name 'citation' (which implies generating references) and ignores three of the four schema parameters (host, json, zone), leaving the true scope ambiguous.

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 or when-not-to-use guidance is provided, and no sibling or alternative tool is referenced even though the sibling list appears to contain overlapping tools (status, normalize, validate). 'Page content is not stored' is a behavior note, not a usage guideline.

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 adds one useful behavioral guarantee ('No identifiers are retained') but does not disclose whether the tool performs side effects, requires network access, or what happens to supplied data beyond retention.

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 with no redundancy. The privacy guarantee is concise and arguably the most decision-relevant fact; every sentence 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 tool with four optional parameters, no output schema, and no annotations, this description is under-specified. It does not explain what result the agent should expect, how the parameters select the classification mode, or why this tool exists alongside citation, normalize, and validate-json.

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 baseline is 3 even though the description adds no parameter-specific meaning. The description doesn't explain how url, host, json, and zone relate to 'classification,' but the schema adequately documents each field's type and intent.

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 verb ('Show') and a resource ('this request'), but leaves the key concept—what 'classified' means for a compatibility tool—unspecified. It does not distinguish the tool from siblings like validate-json or normalize beyond the word 'classified'.

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 guidance is provided on when to use this tool versus the siblings. The description does not mention prerequisites, typical call patterns, or exclusions, so an agent must guess from the parameter names alone.

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 full burden; it does clarify that no WHOIS/ownership lookup is performed, which is a useful behavioral boundary. However, it does not disclose return format, error behavior, or side effects beyond the split operation.

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 no unnecessary words. It is concise, though it sacrifices necessary contextual detail.

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 0 required parameters, 4 optional parameters of different types, no output schema, and no annotations, a one-sentence description is insufficient. The agent cannot determine expected output or which parameters are relevant, especially since url, json, and zone seem unrelated to splitting a hostname.

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 baseline is 3, but the description adds no parameter-level guidance. It does not connect 'hostname' to the host parameter or explain why url, json, and zone are present.

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, 'split a hostname into labels,' and explicitly excludes WHOIS/ownership enrichment, making the core purpose clear. However, it does not differentiate from sibling tools, and the input schema's extra parameters (url, json, zone) introduce ambiguity about the intended input.

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 tool, what inputs to supply, or how it compares to alternatives. The description only states the operation, leaving the agent to infer usage.

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?

No annotations are provided, so the description carries the full burden of explaining behavior. It says nothing about what the tool does with its inputs, whether it returns a list, filters data, or has side effects. This is a complete absence of behavioral disclosure.

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 extremely short and front-loaded, but this is under-specification rather than effective conciseness. One clause cannot convey enough information to invoke a tool correctly, so the brevity does not earn credit.

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 annotations and no output schema, the description is the only source of context. It provides almost none: no operation, no return behavior, no parameter selection guidance. An agent cannot safely or correctly invoke this tool based on the given description.

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 baseline is 3. Each parameter already has a clear description in the schema. However, the description adds no guidance on which of the four optional parameters are relevant to iana-zones, leaving the agent to guess whether url, host, json, or zone should be supplied.

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, not an action. 'Common IANA timezone names for clock calls' vaguely restates the tool name and hints at a use case, but it never states what the tool does, returns, or accepts. It also does not distinguish itself from sibling tools like timezone or utc-time.

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 tool versus alternatives. The phrase 'for clock calls' implies some relationship to time-related siblings, but the description does not say when to choose iana-zones over timezone or utc-time, nor does it provide any exclusions.

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?

There are no annotations, so the description bears the full burden of behavioral disclosure. It does reveal that the tool returns 'group counts only,' which is useful, but it fails to explain failure modes, whether authentication is ever needed, how redirects or missing robots.txt files are handled, or why parameters like 'json' and 'zone' exist. The schema-description mismatch also obscures actual behavior.

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 tight sentence with no filler, and the key output constraint ('group counts only') is front and center. It loses a point because the extreme brevity leaves critical invocation and parameter details unstated.

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 and no annotations, so the description must carry more weight. It does not explain what 'group counts' means, how results are returned, which parameter supplies the robots.txt URL, or how the four schema parameters relate to the tool. The tool is not adequately self-contained for an agent to invoke 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%, which normally earns a baseline of 3, but the parameter descriptions do not align with the stated purpose. For example, 'url' is described as 'HTTPS URL to normalize or cite' rather than as a URL to fetch robots.txt from, and 'json' and 'zone' appear entirely unrelated. An agent cannot confidently determine which parameters to populate when invoking this tool.

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: 'Fetch a public robots.txt and return group counts only.' This clearly identifies the tool's core action and output scope, and distinguishes it from sibling utilities like normalize-url or validate-json. However, the input schema parameters are described in unrelated terms (normalize, cite, validate, timezone), which somewhat muddies the clarity.

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 about when to use this tool versus alternatives, and no mention of prerequisites or exclusions. The word 'public' implies a constraint, but the description does not explain when this tool is preferred over related siblings or what conditions make it inappropriate.

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?

It discloses a key behavior: query and fragment are dropped. With no annotations provided, the description carries the full burden, but it does not mention HTTPS-only constraints, invalid URL handling, or whether the operation is purely read-only. The existing disclosure is useful but incomplete for a no-annotation tool.

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 sentence with zero filler. It front-loads the primary result (origin, host, path) and adds the dropping behavior, making it easy to scan while remaining compact.

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?

The description is incomplete for a tool with 4 parameters, no annotations, and no output schema. It covers only the 'url' concept and ignores the host, json, and zone parameters, which appear unrelated to URL normalization. An agent would be uncertain how to populate or interpret these fields.

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%, giving each parameter a description, so the baseline is 3. The tool description adds no parameter-specific meaning and does not help reconcile the presence of host, json, and zone with a URL-normalization tool, though the schema descriptions themselves are self-explanatory.

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 clear, specific outcome: 'Return origin, host, and path for a URL. Query and fragment are dropped.' This distinguishes it from generic URL helpers and other sibling tools like validate-json. The verb 'return' plus the exact extracted components make the tool's purpose unmistakable.

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 tool should be used when you need the origin, host, or path of a URL and want query/fragment removed. However, it gives no explicit when-to-use/when-not-to-use guidance and names no alternatives, so an agent must infer the usage context.

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 provided, the description carries the full burden of behavioral disclosure. It does disclose that input is discarded, which is a useful privacy-related cue, but it says nothing about whether the operation is read-only, what it returns, how failures are reported, or what 'ok' actually signifies.

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 very short, but brevity is not structure: it is a noun phrase with no verb and no result. The under-specification outweighs the conciseness, even though 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, no annotations, and four optional inputs, so the description must carry most of the context. It fails to state what the caller receives, how success is signaled, or which parameter to populate. An agent can guess the domain but cannot call this tool with confidence.

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 schema already describes all four parameters with 100% coverage, so the baseline is 3. However, the description adds no parameter-level meaning: it does not clarify how url, host, json, or zone relate to the SHA-256 operation, nor which field is the 'input' to be hashed or discarded.

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 an algorithm ('SHA-256') and a data-handling behavior ('input discarded'), but it never states the action or the result. It does not say whether the tool computes a hash, validates a checksum, or returns an OK status, and it identifies no specific resource. The phrase is a fragment, closer to a tag than an explanation.

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 no guidance on when to use this tool or when to prefer a sibling such as validate-json or normalize-url. There are no prerequisites, exclusions, or context about the appropriate input type.

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?

No annotations are provided, so the description must carry the full burden of behavioral disclosure. The word 'catalog' implies a read-only reference, but the description does not state whether parameters are used to filter, whether network calls occur, what output is returned, or whether the tool has any side effects. The input schema hints at validating and discarding data, but the description itself is silent on behavior.

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 short and front-loaded, with no wasted words, which is structurally clean. However, the brevity is under-specification rather than effective concision because it omits the relationship between the stated purpose and the four-parameter schema. It is concise but not complete enough to be genuinely useful.

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 tool with four parameters, no annotations, and no output schema, a five-word description is grossly inadequate. It does not explain the return format, how to select among parameters, what the catalog contains, or how this tool relates to sibling tools. An agent has almost no basis for a correct invocation.

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 already has a clear individual definition. However, the tool description adds no parameter guidance and, more importantly, its HTTP-status-code framing does not clarify why URL normalization, JSON validation, or timezone names are accepted inputs. The schema is helpful in isolation, but the description fails to connect these parameters to the tool's purpose.

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 'Short catalog of common HTTP status codes' is essentially a restatement of the tool name and adds only 'common HTTP'. It lacks a clear verb or action and does not explain why the input schema contains url, host, json, and zone parameters, which are unrelated to a simple status-code catalog. An agent cannot determine the actual function or scope of the tool from this text.

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 provides no guidance on when to use this tool versus any of the sibling tools such as validate-json, normalize-url, or iana-zones. There is no mention of conditions, alternatives, or exclusions, so an agent must guess the appropriate invocation context.

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?

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions the read-style nature of the tool but says nothing about output format, invalid-zone handling, default behavior, or the presence of seemingly unrelated schema parameters like url, host, and json.

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 compact sentence with no filler and is easy to parse. It is concise and front-loaded, though the brevity sacrifices important usage and behavioral context.

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 tool with no annotations, no output schema, and four optional parameters that are not clearly aligned with the description, this is too thin. An agent would not know which parameter to use, whether the other parameters are ignored, or what the returned time format will be.

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 baseline is 3 even without parameter details in the description. The phrase 'named IANA timezone' loosely maps to the zone parameter, but the description adds no real semantic value beyond the schema and does not clarify why url, host, or json exist.

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 states the core behavior: returning the current time for a named IANA timezone. It is specific enough to convey the tool's function, though it does not explicitly differentiate it from sibling tools such as utc-time or iana-zones.

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 tool versus alternatives like utc-time or iana-zones. The description explains what the tool does but provides no context for selection, exclusions, or preconditions.

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?

No annotations exist, so the description must carry the behavioral burden. It fails to disclose that the four input parameters (url, host, json, zone) appear irrelevant to a UTC timestamp and does not specify whether they are ignored. It also does not state whether the operation is read-only or what output format is returned.

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 very short and contains no filler, which is efficient. However, its brevity is under-specification because it omits critical information about parameters and output format, so it is not maximally effective.

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 simple tool, the description is incomplete: it does not specify the timestamp format, clarify that the parameters are irrelevant, or relate the tool to sibling time-related tools. The presence of four unrelated parameters with no explanation makes it insufficient for an agent to invoke confidently.

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 schema documents all four parameters with 100% coverage, which normally sets a baseline of 3, but the parameters are clearly unrelated to a UTC timestamp and look copied from other tools. The description adds no explanation of their role or relevance, so the agent cannot tell if they affect the result. This creates confusion rather than clarity.

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 states the tool returns the current UTC time, which is a specific resource. It is unambiguous about the result, though it lacks a verb. It does not differentiate from the sibling tool 'timezone', so it falls short of full purpose clarity.

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 tool versus alternatives like 'timezone' or other siblings. No context, conditions, or exclusions are provided, leaving the agent to infer usage entirely.

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 disclosure burden. It usefully states that the body is discarded, signaling no persistence, but it does not say what the tool returns, whether the check has side effects, or whether it is local or remote.

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 with no filler. The core purpose is front-loaded, and the second sentence adds a genuinely useful behavioral note without bloating the definition.

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 4-parameter tool with no output schema and no annotations, this is too thin. It does not identify json as the parameter to pass, explain the return value, or clarify why url, host, and zone exist in the schema. An agent is likely to be confused by the unrelated parameters.

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?

Although schema coverage is 100%, the parameter descriptions are at odds with the tool's purpose: url, host, and zone are clearly unrelated to validate-json. Only json is relevant, and its description mostly restates the tool description. The description never tells the agent to ignore the unrelated fields.

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 ('check whether') on a clear resource ('a body is valid JSON'), which is reinforced by the tool name. It does not contrast with sibling tools, so it misses the distinguishability bar for 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?

The intended use is implied by 'Check whether a body is valid JSON' — an agent can infer when to use it. However, there is no guidance on when not to use it or which sibling tools might be alternatives.

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