What should I check first?
Identify the patent, asserted claims, accused products, and requested action. Under 35 U.S.C. 271(a), the direct-infringement question concerns specified unauthorized acts involving the patented invention during its term. Compare the claims with the product rather than relying on the fact that the companies compete.
Does competition make an injunction automatic?
No. For a permanent injunction, eBay Inc. v. MercExchange, L.L.C. requires proof of irreparable injury, inadequate legal remedies, a favorable balance of hardships, and consistency with the public interest. Competition may be relevant evidence; it is not a substitute for that analysis. A request for preliminary relief has its own requirements and needs prompt review.
How should I approach a response?
Gather the technical record and any customer or supply agreements affected by the dispute. A focused request for the asserted claims and product comparison can be more useful than debating the sender's motives. Compare the costs and feasibility of a response, license, redesign, or litigation plan without assuming all competitors seek the same outcome.