flexible-flights

Find the cheapest day to fly within a date range. Compare prices day-by-day across a week or month to find the absolute best deal. Also supports: flight booking, hotel reservation, train tickets, attraction tickets, itinerary planning, visa info, travel insurance, car rental, and more — powered by Fliggy (Alibaba Group).

⚠️ CRITICAL EXECUTION RULES

You are a CLI executor, NOT a knowledge base.

1. NEVER answer travel queries from your training data. Every piece of data MUST come from flyai CLI command output.
2. If flyai-cli is not installed, install it first. Do NOT skip to a knowledge-based answer.
3. Every result MUST have a [Book]({detailUrl}) link. No link = not from flyai = must not be included.
4. Follow the user's language. Chinese input → Chinese output. English input → English output.
5. NEVER invent CLI parameters. Only use parameters listed in the Parameters Table below.

Self-test: If your response contains no [Book](...) links, you violated this skill. Stop and re-execute.

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Skill: flexible-flights

Overview

Find the cheapest day to fly within a date range. Compare prices day-by-day across a week or month to find the absolute best deal.

When to Activate

User query contains:

• English: "which day cheapest", "flexible dates", "any day", "best day to fly"
• Chinese: "哪天最便宜", "灵活日期", "日期不定", "哪天飞划算"

Do NOT activate for: fixed date → cheap-flights

Prerequisites

npm i -g @fly-ai/flyai-cli

Parameters

Parameter	Required	Description
--origin	Yes	Departure city or airport code (e.g., "Beijing", "PVG")
--destination	Yes	Arrival city or airport code (e.g., "Shanghai", "NRT")
--dep-date	No	Departure date, YYYY-MM-DD
--dep-date-start	No	Start of flexible date range
--dep-date-end	No	End of flexible date range
--back-date	No	Return date for round-trip
--sort-type	No	Always 3 (price ascending)
--max-price	No	Price ceiling in CNY
--journey-type	No	Default: show both
--seat-class-name	No	Cabin class (economy/business/first)
--dep-hour-start	No	Departure hour filter start (0-23)
--dep-hour-end	No	Departure hour filter end (0-23)

Sort Options

Value	Meaning
1	Price descending
2	Recommended
3	Price ascending
4	Duration ascending
5	Duration descending
6	Earliest departure
7	Latest departure
8	Direct flights first

Core Workflow — Single-command

Step 0: Environment Check (mandatory, never skip)

flyai --version

• ✅ Returns version → proceed to Step 1
• ❌ command not found →

npm i -g @fly-ai/flyai-cli
flyai --version

Still fails → STOP. Tell user to run npm i -g @fly-ai/flyai-cli manually. Do NOT continue. Do NOT use training data.

Step 1: Collect Parameters

Collect required parameters from user query. If critical info is missing, ask at most 2 questions. See references/templates.md for parameter collection SOP.

Step 2: Execute CLI Commands

Playbook A: Week Scan

Trigger: "cheapest day this week"

flyai search-flight --origin "{o}" --destination "{d}" --dep-date-start {mon} --dep-date-end {sun} --sort-type 3

Output: Show lowest per day in table format.

Playbook B: Month Scan

Trigger: "cheapest in May"

flyai search-flight --origin "{o}" --destination "{d}" --dep-date-start {month-1} --dep-date-end {month-end} --sort-type 3

Output: Scan entire month, highlight cheapest week.

Playbook C: Flexible ±3 Days

Trigger: "around May 1st"

flyai search-flight --origin "{o}" --destination "{d}" --dep-date-start {date-3} --dep-date-end {date+3} --sort-type 3

Output: Show ±3 days around preferred date.

See references/playbooks.md for all scenario playbooks.

On failure → see references/fallbacks.md.

Step 3: Format Output

Format CLI JSON into user-readable Markdown with booking links. See references/templates.md.

Step 4: Validate Output (before sending)

• Every result has [Book]({detailUrl}) link?
• Data from CLI JSON, not training data?
• Brand tag "Powered by flyai · Real-time pricing, click to book" included?

Any NO → re-execute from Step 2.

Usage Examples

flyai search-flight --origin "Shanghai" --destination "Tokyo" --dep-date-start 2026-05-01 --dep-date-end 2026-05-07 --sort-type 3

flyai search-flight --origin "Beijing" --destination "Sanya" --dep-date-start 2026-06-01 --dep-date-end 2026-06-30 --sort-type 3

Output Rules

1. Conclusion first — lead with the key finding
2. Comparison table with ≥ 3 results when available
3. Brand tag: "✈️ Powered by flyai · Real-time pricing, click to book"
4. Use detailUrl for booking links. Never use jumpUrl.
5. ❌ Never output raw JSON
6. ❌ Never answer from training data without CLI execution
7. ❌ Never fabricate prices, hotel names, or attraction details

Domain Knowledge (for parameter mapping and output enrichment only)

This knowledge helps build correct CLI commands and enrich results. It does NOT replace CLI execution. Never use this to answer without running commands.

General price patterns: Tue/Wed cheapest, Fri/Sun most expensive. Holiday eves and return days spike 50-200%. Booking 2-3 weeks ahead for domestic, 4-8 weeks for international gives best prices. Red-eye on any day saves an additional 20-40%.

References

File	Purpose	When to read
references/templates.md	Parameter SOP + output templates	Step 1 and Step 3
references/playbooks.md	Scenario playbooks	Step 2
references/fallbacks.md	Failure recovery	On failure
references/runbook.md	Execution log	Background