Byteplant Validator MCP Server

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

Annotations only declare readOnlyHint and openWorldHint, but the description discloses the full failure surface: DELAYED, NO_COUNTRY, RATE_LIMIT_EXCEEDED, API_KEY_INVALID_OR_DEPLETED, RESTRICTED, INTERNAL_ERROR, and concrete rate-limit numbers (100 requests / 300s, with remaining count and seconds). It also explains that corrections are unavailable for INVALID/ambiguous input, which is meaningful operational context an agent needs to handle responses.

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 sentence is well front-loaded, but the bulk of the text is a field-by-field enumeration of return values, which is redundant because an output schema already exists. The status-code semantics are worth keeping; the remaining per-field listing does not earn its space.

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 an output schema present, the description is not obliged to explain return values, and it still adds useful status semantics and rate-limit behavior. The main gap is the absence of any input-parameter guidance for a tool with 11 parameters, but the schema covers most of 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?

Schema description coverage is 73%, which is close to the high-coverage band where the schema does the heavy lifting, and the description adds nothing about input parameters at all. Notably it does not compensate for the undocumented city, state and postal_code fields, so it lands at the baseline rather than above it.

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 first sentence states a specific verb+resource ('validate and standardize a postal address') plus the return shape (status, standardized components, optional coordinates). Against siblings validate_email and validate_phone the resource alone is unambiguous, so an agent can route correctly without opening the schema.

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 or when-not sentence; usage is only implied by the name and by the note that coordinates are returned only 'for valid addresses if Geocoding is enabled'. The geocoding conditional is the closest thing to a usage rule, so the score sits at implied-usage level rather than clear 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 only supply readOnlyHint and openWorldHint, so the description carries the rest and does so well: it documents rate-limit behavior (100 requests per 300s), the ratelimit_remain/ratelimit_seconds fields, and specific error codes (401 missing address, 118 rate limited, 119 invalid/depleted API key, implying an API key is required). That is meaningful operational 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?

The core purpose is front-loaded in one sentence, but the bulk of the body is an enumerated list of result fields, which duplicates the existing output schema and does not earn its place in a tool description. Structure is readable but somewhat bloated with redundant return-value documentation.

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 two-parameter read-only validation tool, the description covers error semantics, rate limiting, and the meaning of the category enum, which is enough for correct invocation. The return-value section is redundant given the output schema, but nothing essential 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% (email and timeout both documented in the schema), so the baseline is 3. The description adds nothing about the timeout parameter or accepted email formats, but it does explain what the operation does with the address, so it is not below baseline.

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 opens with a concrete verb+resource: 'Validate an email address and return info about it.' The resource (email) is distinct from the sibling tools validate_address and validate_phone, so an agent can route correctly even though siblings are never named explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no statement about when to use this tool versus validate_address or validate_phone, and no prerequisites or exclusions are given. Usage is only inferable from the name and first sentence, which is the minimum implied context rather than real 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 readOnlyHint=true and openWorldHint=true, so safety is already covered, and the description adds genuinely useful behavior: enumerated status outcomes (RATE_LIMIT_EXCEEDED, API_KEY_INVALID_OR_DEPLETED, DELAYED) and explicit rate-limit semantics (100 requests per 300s). This tells the agent what failure and throttling look like, which the annotations do not.

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 lead sentence is front-loaded and efficient, but the bulk of the text enumerates result fields that duplicate the existing output schema. That enumeration is largely redundant and crowds out more valuable guidance such as when to use express vs extensive.

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 an output schema present, the description need not re-explain return values, and it covers the core purpose plus rate-limit behavior. The main gap is the absence of usage guidance for mode selection and country-code handling, but the tool is otherwise callable as described.

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 phone, code, mode, locale, and timeout. The description adds no parameter-level meaning beyond that, 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 ('validate') and resource ('phone number') plus the returned data categories, so an agent can immediately distinguish it from validate_email and validate_address by resource. It does not explicitly name siblings, but the resource is unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no when-to-use guidance, no prerequisites, and no exclusions. It never explains the tradeoff between the extensive and express modes that the schema exposes, nor when a country code is needed beyond what the schema already says.

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