Convert a UTC or ISO datetime into a formatted date and time string for any IANA time zone. Provide the date and target zone to get the localized result.
Convert a UTC/ISO date into a formatted date+time string for any IANA time zone
| Name | Required | Description | Default |
|---|---|---|---|
| date | Yes | ISO 8601 date/datetime | |
| timeZone | Yes | IANA time zone name, e.g. "America/New_York", "Asia/Tokyo" |
Changes observed during successful MCP inspections.
v2.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description bears the full responsibility for behavioral disclosure. It states the conversion and result, but it does not specify the output format, behavior on invalid timezones, or how input offsets are interpreted, leaving some uncertainty.
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 that contains no filler words and communicates the action, input, and result efficiently. It is well-structured and easy to parse.
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 tool is simple, with only two fully documented parameters. The description indicates the return type ('formatted date+time string') but stops short of specifying the exact format (e.g., 'YYYY-MM-DD HH:MM:SS'). Given the lack of an output schema, a tiny bit more detail would make it fully self-contained, but this is sufficient for a straightforward conversion.
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%, with both parameters fully described in the input schema. The description adds no additional semantic meaning beyond 'date' and 'timeZone' as specified in the schema, so the baseline score 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?
The description states a specific verb ('convert'), resource ('a UTC/ISO date'), and outcome ('formatted date+time string for any IANA time zone'). This makes it unmistakably distinct from siblings like convert_timestamp or parse_date without needing to inspect schemas.
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 when to use the tool: whenever a UTC/ISO date needs to be presented in a particular IANA timezone. However, it does not explicitly name alternatives or state when not to use it, leaving the decision to the agent's familiarity with the sibling set.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.