Look up a timezone by IANA name and return its current UTC offset, DST state and local time. Pure CPU, instant.
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"q": "<q>"
},
"name": "timezone"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| q | Yes | IANA timezone name |
Changes observed during successful MCP inspections.
Input schema / properties / qAdded value: +{
+ "description": "IANA timezone name",
+ "type": "string"
+}Input schema / requiredAdded value: +[
+ "q"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and does reasonably well: "Pure CPU, instant" tells the agent there is no network call, no rate limit, and no latency concern, and "look up" implies a side-effect-free read. It does not disclose error behavior for an invalid or unknown IANA name, nor whether aliases/abbreviations 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 sentences with the identity of the operation front-loaded and the return values and cost profile following immediately. Every clause carries information; nothing is 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?
For a one-parameter lookup with no output schema, the description covers what goes in, what comes back, and the operational cost. The only meaningful gap is failure behavior on bad input, which is minor for a stateless CPU-only tool.
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 single parameter q is already documented as "IANA timezone name", so the schema does the heavy lifting. The description restates the same constraint ("by IANA name") without adding format examples or handling notes, so the baseline of 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 and resource ("look up a timezone by IANA name") plus the exact return payload (UTC offset, DST state, local time), which is far more than the bare name conveys. It does not explicitly distinguish itself from close siblings like convert_timezone, time_convert, or timestamp, so the differentiation is only implicit.
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 phrase "by IANA name" implies the usage context (resolve a named zone to its current offset/DST status), but there is no explicit when-to-use, no when-not-to-use, and no named alternative. An agent facing convert_timezone and time_convert alongside this tool gets no routing help from the description.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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