Help: You need a passphrase to unlock the secret key for...

I did not store my private key on keybase, is this a supported option at this time? I also may not know what I'm doing. I have an email from a keybase user (we're mutual "trackers" in kb), and the apple mail client (as well as the command line decrypt) tells me You need a passphrase to unlock the secret key for user: "keybase.io/tgm tgm@keybase.io" (that's me, as you'll see i've verified myself on gh) or in the case of apple mail: "Secret key to decrypt the message is missing." "None of the following secret keys could be found in your keychain (XXXXXXXX). The secret key is needed to decrypt this message.

Please check with the sender that they used your correct public key.
Check any backup of your keychain, and try to import the secret key from there."

I doubt highly the sender messed up. I think perhaps I have misconfigured, any suggestions? I don't mind trashing my current keys, and attempting to start over, but i'd rather understand this a little better.

(also, is this where I should try to discuss this sort of issue?)

The issue names no repository files, tests, or entry points. Start by reproducing the Apple Mail and command-line decrypt reports and comparing the available keychain/private-key state with the sender's public key. Done means a documented diagnosis and a confirmed supported setup or a clearly isolated client defect.

Written by the indexing model from the issue text.