Yay... finished it! :)
I can't use has_not_created, as it's possible to read the parchment without removing it from the tin box. Instead, I set a boolean the first time it's read and the magic word only takes effect if the boolean is set (i.e. if the parchment has been read). This is hinted at with an extended message the first time the parchment is read. I had been thinking about doing this anyway, but your suggestion prompted me to implement it. Thank you.
I'm as guilty of this as any other author, but my rule of thumb is... if the response to an input includes the EXACT words that a player may have tried then you have to program that input in if possible, otherwise they're going to feel annoyed/cheated. So as the response includes "You strike the flint and...", I think you have to include STRIKE FLINT... even if it's just a response that says "What do you want to light?" or "You create some sparks with the flint. Definitely enough to start a fire."... which lets them know they're proceeding along the right sort of lines.
5 years ago(+2)
Fixed now. You can now STRIKE ROCK with flint or STRIKE FLINT with rock. Possible outcomes are a sore hand, a shower of sparks or a lit branch, depending on what's held and what's present. Synonyms include HIT, BASH, CRACK, CRASH and SMASH. I think that pretty well covers it.
5 years ago(+1)
I've added ROW/PADDLE BOAT, PEEL APPLE and CUT/CHOP/SHARPEN BRANCH.
Thanks for the comments.