The seller agreed to terms, the investor walked, and the lead fee came down to whether it was a lead anymore

The tail period is the answer, but the tail has to define "same buyer chain" or it becomes unenforceable the moment a wholesaler touches the address.

The agreement did the work here, and it was written entirely in the investor's favor. A contract-contingent fee with no tail period and no re-engagement clause means the bird dog's deliverable, a motivated seller at a real address, only gets compensated if that specific investor performs. The investor's process killing the deal reset the fee clock to zero, which is the logical outcome of the language even if it is a bad outcome for the bird dog.

The assumption doing the most work in that original agreement is that the investor and the bird dog share the same definition of "lead conversion." The investor defined it as a signed purchase contract. The bird dog's actual deliverable, access to a motivated seller who then stayed motivated for six weeks and sold, never made it into the agreement at all.

Two structural fixes are worth understanding.

First, a milestone-based fee splits payment across the relationship rather than concentrating it at close. A smaller amount at verified first contact, with the balance contingent on a signed contract, gives the bird dog partial compensation for a real introduction even when the investor fumbles the execution. What that split looks like is a negotiation, and it has to be in writing before the first handoff.

Second, a tail period with explicit re-engagement language covers exactly the six-week scenario. If any buyer closes on an address the bird dog introduced within a defined window, the fee applies. Ninety to 180 days is a common framing, but confirm with your attorney what language holds in your jurisdiction, because enforceability varies and this is a contract drafting question that requires a licensed professional.

The part the original post did not mention: a fee tied to first contact only works if the bird dog can document the introduction. Date-stamped written communication, a signed receipt from the investor, something that establishes priority. Without it, the tail period language has nothing to anchor to.

What did the original agreement say about documentation of the handoff itself?

The question the agreement should have answered is who owns the introduction, not who owns the closing. If the deliverable is a motivated seller at a specific address, the fee attaches to that address being transacted, regardless of which buyer gets there next, and a 90 to 180 day tail window written against the property address rather than against a specific investor is how you protect that. The tail does not need to name every possible buyer; it needs to say that any closing on that parcel within the window triggers the fee from whoever the bird dog handed the lead to originally, because that person's pass creates the opening for the next one.

The harder mechanical problem is collection when the original investor walks and a stranger closes. The bird dog has no privity with the wholesaler or the second investor, so a property-address tail only works if it runs against the first investor as an obligation, meaning the first investor owes the fee if the property closes within the tail, period, regardless of who the buyer ends up being. That shifts the first investor's incentive: walking no longer costs nothing, which is exactly the alignment you want when the fee is meant to price the introduction and not the outcome.

Before running this structure, confirm with an attorney in your state that the fee arrangement does not trigger finder's fee or real estate licensing statutes, because several states treat compensation for connecting buyers and sellers as brokerage activity. What does your current written agreement say about re-engagement, if anything?