The Vendor Negotiation Prep

Prepare me to negotiate with this supplier/vendor.

What I'm buying: [DESCRIBE]
The current terms/offer: [DESCRIBE]
My leverage: [VOLUME, ALTERNATIVES, RELATIONSHIP, TIMING]

Provide:
1. The levers I have (competition, volume, term length, payment terms,
   bundling)
2. The full set of terms to negotiate beyond price (SLAs, flexibility,
   exit, support)
3. A target and walkaway, with the market context to verify
4. How to use competitive alternatives without poisoning the relationship
5. The opening approach and key asks

Help me negotiate total value and terms, not just squeeze the unit price
(which suppliers claw back elsewhere).