Japan Weather Forecast MCP

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

No annotations are provided, so the description carries the full disclosure burden. It does not state the authentication requirement explicitly (only the schema's access_token field hints at it), what happens if more than 8 prefectures are supplied, whether calls count against a quota, or what the response contains. For a PRO-tier tool, the subscriber gating should be spelled out.

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 leading 'PRO.' token is terse to the point of being cryptic, 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?

With no annotations and no output schema, the description must cover behavior and results on its own, and it does not. An agent still cannot tell what a forecast contains, how errors (e.g. 9 prefectures, invalid token) are surfaced, or how this relates to the sibling tools.

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 50%: access_token is documented in the schema, while 'prefectures' has no schema description. The description compensates partially by stating the maximum of 8 items, which is real added meaning not encoded in the schema. It says nothing about accepted name formats, duplicates, or ordering of results.

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 the verb 'Forecasts' and a scoping limit ('up to 8 prefectures'), so the batch nature is visible. But it never says what is being forecast or how it differs from the sibling tool 'forecast', leaving the agent to infer that this is the multi-prefecture variant. 'PRO' is a tier marker, not a purpose statement.

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 on when to choose this over the sibling 'forecast' or 'overview'. The only implicit cue is 'PRO', which hints at a subscriber requirement but does not state it as a condition. The agent must guess whether batch is preferred for multiple prefectures or whether forecast also accepts lists.

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 must carry the burden; 'FREE' usefully signals no billing/quota cost and 'short-term' bounds the forecast horizon. It omits whether an API key or auth is needed, what happens for unknown prefectures, and what the response contains.

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?

One tightly packed sentence with the cost signal front-loaded and the scope immediately after. Nothing is redundant.

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 no-annotation, no-output-schema tool of this simplicity, this is close to sufficient, but the agent still gets no hint about return fields, time granularity (today/tomorrow), or language of the results.

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% and 'prefecture' is a bare string, but the description supplies both the meaning (a Japanese prefecture) and the default (Tokyo). That is the essential semantic an agent needs for the single parameter.

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?

Names a specific verb+resource: JMA short-term weather forecast scoped to a single prefecture. The scope ('for a prefecture') implicitly separates it from batch_forecast, but it never names or contrasts with either sibling 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?

States a default (Tokyo) which tells the agent the parameter is optional, and 'for a prefecture' implies single-location use. It never says when to prefer batch_forecast or overview, nor when this tool should be avoided.

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. It does not say what the textual overview actually contains, whether it is free-form prose, its length or format, or how failures/lapsed subscriptions surface. The "PRO." prefix hints at a paid-tier/auth requirement, but that is only clarified indirectly by the access_token schema description, not by the tool description.

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?

It is a single short sentence, so nothing is wasted, but the lead token "PRO." is cryptic and the sentence is under-specified rather than efficiently front-loaded. Brevity here comes at the cost of comprehension.

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 output schema, no annotations, and an undocumented required parameter, the description should explain the return form (textual bulletin? narrative summary?) and the forecast horizon. Neither is present, so an agent cannot predict what it will get back or how it differs from `forecast`.

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 50%: `access_token` is documented in the schema (subscriber token from /success or Bearer), while `prefecture` has no description at all. The description reiterates that the tool targets a prefecture, which confirms the parameter's role but adds no format details (e.g., Japanese prefecture names in English or kanji).

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?

"JMA textual overview forecast for a prefecture" names a resource (textual overview forecast) and scopes it to a prefecture, so the general nature is inferable. However, it never distinguishes itself from the sibling `forecast` or `batch_forecast` — what makes this an "overview" versus a plain forecast is left to guesswork, and "PRO." is unexplained jargon.

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 of when to use this tool versus `forecast` or `batch_forecast`, nor any prerequisites beyond the implicit hint in "PRO." The agent must infer that "overview" is the summary-grade variant, which is not stated anywhere.

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