| name | time-conversion |
| description | Timezone and time conversion specialist for accurate, DST-aware time calculations worldwide. Use when asked to: convert a time between timezones, get the current time in a city or region, schedule meetings across multiple timezones, or check UTC offsets and daylight saving status. Trigger keywords: time-conversion, time-conv. Do NOT use for calendar arithmetic (adding days/weeks) — use a general reasoning approach instead.
|
| compatibility | Requires MCP server called time configured in .codex/mcp-config.json. |
Time Conversion Skill
Description
Convert times between any IANA-defined timezones and retrieve the current time in any
location using the time MCP server. All conversions are DST-aware and sourced from the
IANA timezone database, ensuring accuracy for both past and future dates where database
coverage exists.
Capabilities
- Convert a specific time from one timezone to one or more target timezones
- Retrieve the current time in any IANA timezone
- Handle daylight saving time transitions automatically
- Resolve city or region names to their canonical IANA timezone identifiers
- Support multi-timezone comparisons (e.g., finding overlap windows for international meetings)
Key Concepts
- IANA timezone name: The canonical identifier for a timezone (e.g.,
America/New_York, Europe/London, Asia/Tokyo) — always prefer over ambiguous abbreviations like EST or BST.
- UTC: The universal reference point; when in doubt, convert to UTC first then to the target.
- DST: Daylight Saving Time — the MCP server handles transitions automatically when IANA names are used; UTC offsets (e.g.,
+05:30) do not account for DST.
get_current_time: MCP tool to retrieve the current time in a given IANA timezone.convert_time: MCP tool to convert a specific time from a source timezone to a target timezone.
Workflow
- Connectivity probe — call
get_current_time with timezone UTC as the first action. If it fails, stop immediately and report: "Time conversion MCP server is unavailable. Cannot proceed."
- Resolve timezone names — map any city names, abbreviations, or UTC offsets in the user's request to canonical IANA names before calling the tools.
- Select the right tool:
- Use
get_current_time for "what time is it now in X?"
- Use
convert_time for "convert HH:MM from X to Y"
- Handle multi-timezone requests — call
convert_time (or get_current_time) once per target timezone; batch results into a single response table.
- Report using this structure:
- Result: converted time(s) with timezone name and UTC offset
- DST note: flag if a DST transition is relevant to the result (e.g., clocks change within the next week)
- Reference: IANA names used, for verification
Usage Examples
Current Time in a City
time-conv What time is it now in Tokyo?
Basic Conversion
time-conv Convert 3:00 PM EST to Tokyo time
Multi-Timezone Meeting
time-conv What time is 10 AM New York in London, Tokyo, and Sydney?
ISO Timestamp Conversion
time-conv When is 2026-02-15 00:00 UTC in America/Los_Angeles?
DST Awareness
time-conversion Is Europe/London currently on GMT or BST?
Configuration
MCP server is called time and is configured in .codex/mcp-config.json.
No sensitive environment variables are required for this skill.
Best Practices
- Always use IANA timezone names — abbreviations like
EST, BST, IST are ambiguous and should be resolved to IANA names before calling tools
- Always run a connectivity probe (
get_current_time UTC) before executing the user's request
- Prefer
convert_time over manual offset arithmetic — let the MCP server handle DST automatically
- Present results in a table when converting to multiple timezones simultaneously
- Flag DST transitions when a conversion date falls near a clocks-change boundary
Limitations
- Relies on the IANA timezone database; historical timezone changes before database coverage may be incomplete
- Future DST rule changes (e.g., countries abolishing DST) take effect only after a database update
- Cannot perform calendar arithmetic (adding/subtracting days or weeks) — use general reasoning for that
- UTC offsets (e.g.,
+05:30) are accepted but treated as fixed — DST is not applied when using raw offsets
