Japan Reverse Geocode MCP

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

With no annotations, the description carries the full burden. It usefully discloses the 50-point cap, which is a real batch constraint, and the word 'reverse-geocode' implies a read-only operation. However, it says nothing about rate limits, per-call cost/credits for a PRO tool, or failure behavior when a point is invalid.

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 tight sentence with the defining constraint (batch size) front-loaded, plus a tier tag. Nothing is wasted, though 'PRO.' is unexplained noise to an agent.

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 whose primary input is a structured array and with no output schema, the description omits both the per-point object shape and any indication of what the response contains. An agent could form the call but not confidently build the points array.

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 only 50%: access_token is documented in-schema, but 'points' is an untyped array of bare objects with no field structure anywhere. The description does not explain what each point object must contain (lat/lon keys, ordering), so the most important parameter is left ambiguous.

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 (reverse-geocode) and resource (up to 50 lat/lon points), with the batch cap of 50 made explicit. It is distinguishable from siblings by the 'batch' framing, but never names reverse_geocode or reverse_with_elevation to make the contrast explicit.

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 'up to 50 points' phrasing implies this is for multi-point lookups rather than single lookups, but it never states when to prefer it over reverse_geocode or reverse_with_elevation. The 'PRO.' prefix hints at a premium/subscriber tier without explaining any gating condition.

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 usefully discloses cost ('FREE') and the Japan-only coverage constraint, which are genuine behavioral facts. It omits what happens for out-of-bounds coordinates (error vs null), precision of the municipality match, and any rate limits — meaningful gaps for a lookup tool with zero annotation coverage.

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 clauses, front-loaded with the cost signal and then the action, scope, and outputs. No filler; every element 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?

No output schema exists, so the description is the only place return values are described — it names the two outputs but not their shape, encoding, or fallback behavior when no municipality matches. Adequate for a simple 2-param lookup but leaves real gaps.

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 0%, so the description must compensate. It adds the important constraint that coordinates must be within Japan, but gives no datum, decimal-degree convention, or accepted range for lat/lon. The parameter names are largely self-explanatory, which keeps this at an adequate 3 rather than lower.

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 (reverse-geocode) and resource (lat/lon) and names the exact outputs (municipality code, local name) plus a geographic scope (Japan). It implicitly distinguishes itself from batch_reverse (single point) and reverse_with_elevation (no elevation), but never names those siblings, so an agent must infer the boundary.

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 'in Japan' qualifier and the singular lat/lon imply when this tool applies and that out-of-Japan coordinates are out of scope, but there is no explicit when-not clause or pointer to batch_reverse for multiple points. Usage is implied rather than stated.

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 disclosure burden. 'PRO.' hints at a subscriber/tiered capability and access_token implies auth, but the description never states whether the token is mandatory, what happens without it, what the response contains (address fields? elevation units/datum?), or any rate limits.

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 the core operation front-loaded and no filler. It is efficient, though the terseness contributes to the under-specification elsewhere.

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 annotations and no output schema, the definition is too thin: it omits auth requirements, the shape/units of the elevation result, and the geocode output. An agent could invoke it but could not predict what it returns or how failures manifest.

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 only 33% — lat and lon have no documented format, coordinate system, or precision expectations, and the description adds nothing about them. Only access_token is described, and that comes from the schema, not the description.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific compound operation (reverse geocode + elevation lookup) and scopes it with 'for one point,' which implicitly separates it from the batch sibling. It stops short of naming reverse_geocode or batch_reverse, so the differentiation is inferential rather than explicit.

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-to-use guidance. An agent must infer from 'one point' that batch_reverse handles multiple points and that plain reverse_geocode lacks elevation, but neither alternative is named or conditioned.

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