---
name: datetime
description: Use the `date` command via Bash tool whenever you or the user mention time, dates, or temporal concepts. Verify current date/time before ANY temporal response, as environment context may be outdated. Parse expressions like "tomorrow", "next week", "3 days", "in 2 weeks", "next Monday at 3pm". Proactively invoke for deadlines, schedules, time-sensitive tasks, week numbers, or any date/time reference.
allowed-tools: Bash
---

# DateTime Natural Language Parser

Parse natural language date and time expressions using GNU `date` command (native Linux utility).

## IMPORTANT: For Claude Code

**DO NOT invoke slash commands** (`/datetime:parse`, `/datetime:now`, `/datetime:calc`) - those are for users only.

**Instead, use the `date` command directly via the Bash tool:**

```bash
# Get current date/time
date '+%Y-%m-%d %H:%M:%S (%A)'

# Parse natural language
date -d "tomorrow" '+%Y-%m-%d %H:%M:%S (%A)'
date -d "next monday at 9am" '+%Y-%m-%d %H:%M:%S (%A)'
date -d "3 days" '+%Y-%m-%d %H:%M:%S (%A)'
```

This skill provides the command patterns and when to use them. The slash commands are for users to invoke manually.

## When to Use This Skill

Automatically invoke when:
- User mentions temporal expressions: "tomorrow", "next week", "in 3 days"
- Need to verify current date/time
- User references deadlines or time-sensitive tasks
- <env> context shows incorrect dates

## How to Use

Use the Bash tool with `date -d` command:

**Get current date/time:**
```bash
date '+%Y-%m-%d %H:%M:%S (%A)'
```

**Parse natural language:**
```bash
date -d "tomorrow" '+%Y-%m-%d %H:%M:%S (%A)'
date -d "next wednesday" '+%Y-%m-%d %H:%M:%S (%A)'
date -d "3 days" '+%Y-%m-%d %H:%M:%S (%A)'
date -d "next monday 9am" '+%Y-%m-%d %H:%M:%S (%A)'
```

**Important**: The `date` command doesn't understand "in" keyword. When user says "in 3 days", use `"3 days"` instead.

## Output Format

Returns single line: `YYYY-MM-DD HH:MM:SS (DayName)`

Example: `2024-10-29 14:23:45 (Tuesday)`

## Supported Expressions

- Relative: "today", "tomorrow", "yesterday"
- Named days: "next monday", "this wednesday", "last friday"
- Offsets: "3 days", "2 weeks", "5 months ago"
- Complex: "tomorrow 3pm", "next monday at 9am"
- Past: "3 days ago", "last week"

## Error Handling

If `date -d` fails with an invalid expression:

1. **Recognize the failure**: If the command returns an error, inform the user the expression couldn't be parsed
2. **Try alternative approaches**: Check `references/reference.md` for:
   - Date arithmetic examples (if user wants relative calculations)
   - Complex expression syntax (if user wants compound dates)
   - Unix timestamp calculations (if user wants day differences)
3. **Fallback to current date**: If no alternative works:
   ```bash
   date '+%Y-%m-%d %H:%M:%S (%A)'
   ```

**Example error handling:**
```bash
# Try parsing
date -d "user expression" '+%Y-%m-%d %H:%M:%S (%A)' 2>&1
# If error message appears, tell user and suggest checking references/reference.md for advanced patterns
```

## Advanced Usage

For relative calculations, week numbers, and complex date arithmetic, see `references/reference.md`.