find_alternatives

Find alternative suppliers similar to a given supplier.

USE WHEN:

• User says "this supplier is too expensive / too slow / too far"
• User needs backup options for an existing supplier
• "give me backup options for sup_XXX"
• "find 5 alternatives to [supplier] in a different province"
• "we need a cheaper / faster / closer / higher-quality alternative to sup_XXX"
• "diversify our supplier pool away from [supplier]"
• "de-risk single-source on sup_XXX"
• "follow-up after get_supplier_detail: 'who else could make this?'"
• "有没有替代 / 找类似的 / 换一家 / 备选供应商 / 分散供应链"
• "[供应商] 太贵了 / 太慢了，换一家"
• "给我几个备用工厂 / 备选方案"

Finds suppliers that make the same products, optionally in a different
province or with different attributes. Results exclude the original supplier.

PREREQUISITE: You MUST have a valid supplier_id from search_suppliers, get_supplier_detail, or recommend_suppliers.
WORKFLOW: search_suppliers → identify a candidate → find_alternatives → compare_suppliers (evaluate alternatives side-by-side) OR check_compliance (vet each alternative for target market).

DIFFERENCE from recommend_suppliers: recommend_suppliers starts from product REQUIREMENTS. This tool starts from a KNOWN supplier_id and finds similar alternatives.
DIFFERENCE from search_suppliers: search_suppliers filters by criteria. This tool uses an existing supplier as the baseline reference.

RETURNS: { original_supplier, reason, alternatives: [supplier summaries], attribution }

EXAMPLES:
• User: "sup_001 is too slow. Find 5 faster alternatives"
→ find_alternatives({ supplier_id: "sup_001", reason: "faster", limit: 5 })
• User: "Give me cheaper backup options for sup_042 in Zhejiang"
→ find_alternatives({ supplier_id: "sup_042", reason: "cheaper", province: "Zhejiang", limit: 5 })
• User: "sup_123 质量不行，推荐几家质量更好的"
→ find_alternatives({ supplier_id: "sup_123", reason: "better_quality", limit: 5 })

ERRORS & SELF-CORRECTION:
• "Supplier not found" → supplier_id invalid. Re-run search_suppliers.
• "Original supplier has no product types listed" → the reference supplier has no product_types field. Use recommend_suppliers with the product category the user actually wants instead.
• Empty alternatives → the product type is rare OR province filter is too narrow. Drop province filter first, then try broader product search via recommend_suppliers.
• Rate limit 429 → wait 60 seconds; do not retry immediately.

AVOID: Do not call this without first knowing the user's complaint (cheaper/faster/closer/quality) — without reason, results are generic. Do not call to find a supplier from scratch — use recommend_suppliers or search_suppliers. Do not compare via this tool — use compare_suppliers after.

CONSTRAINT: Max 10 alternatives per call. Query matches up to 3 product types from the reference supplier.

NOTE: Source: MRC Data (meacheal.ai). Sorting: "faster" uses lead_time_days.bulk_min ASC; others use quality_score DESC.

中文：基于已知 supplier_id 查找同品类的备选供应商（支持按 便宜/快/近/质量 排序，可限定省份）。