Wrap-up: The Making Of My Spying Girlfriend
This is not a solution to the puzzle, but provides notes from its poser. This type of answer has been approved by the community.
Caution: This post may contain spoilers.
I wasn't going to do a wrap-up on this one but I suddenly remembered a few of the difficulties I had putting it together so I thought I'd share in the hopes that it may help someone else who in a similar situation.
As @Philipp so wisely guessed (it looked for a while as if his comment was going to get more votes than the puzzle) this all came from the gag phrase in the middle. Well done, @Philipp! We were in the midst of a heat wave (what we call a canicule here in Swiss Romande) and I was performing an experiment regarding the effect of apple cider on global warming. All was going well until the classic poem There Was an Old Lady popped into my head as I was reaching for my glass. You may recall that this Old Lady had a "spider inside her". Spider... inside her... cider... I tried to resist but I have a terrible weakness for wordplay.
Alcohol and nursery rhymes aren't a great foundation on which to build a puzzle. Nevertheless, I persevered.
I had "insider in cider inside her". My daughter's favorite Magic School Bus episode involved the bus shrinking and being swallowed. I decided to steal this idea. I needed a narrator to deliver the line, a girl to be "her" and an insider who gets shrunk. Oh, and a puzzle of some kind.
To make it compelling, I wanted to make it necessary to solve the puzzle (which I didn't have) in order to avert disaster. So: girl spy swallows boss, her job is on the line, her boyfriend narrates. Ages ago I wrote a "narrated" puzzle called "My Puzzling Girlfriend". decided to use those characters and a similar title.
The constant problem was that the story part kept growing. I learned how difficult it can be to be brief.
The first idea was that the girlfriend was a "good" spy. A "bad" spy shrank her boss and it was her fault. She captured a coded message for an antidote... too long.
Girlfriend shrinks boss by accident. But why would she be pointing a shrinking device at her boss? How does she know about an antidote? Where does the puzzle come in? (The puzzle I didn't have yet. Dang.)
Start over. Girlfriend has a nutty boss who tries to test a shrink ray on her but shrinks himself accidentally. He planned to unshrink her after the test. He made a puzzle to keep the unshrinker secret because... SPIES! I'm starting to wonder what was in my apple cider because at the time I thought this made sense. (Still no puzzle ideas!!!)
I'm now thinking: narrator and Ada go to office. Dialogue with boss. Accident. Put boss in capsule. Funny bad guys attack. Ada swallows boss. Beat bad guys. Search office. Find note. Can't solve. Way. Too. Long.
I rearranged. I pruned. I condensed. I made the narrator so panicked he almost forgot to give the puzzle. I ended up with what I felt was about the upper limit of what I could expect someone to read before getting to the real puzzle (which I still didn't have).
Spies have codes. I decided make this a code. I needed to go from letters to numbers or vice versa. Maybe because this all started with a poem, I thought about numbered poems. Shakespeare's sonnets have an unambiguous numbering (Milton's, for example, are in two editions with different numberings) and he wrote lots so I could go for ASCII encoding rather than the A-1, B-2 that I originally planned.
I needed a short message since it takes four words to signal a single letter. I left the spaces out of the message because it looked weird to have so much repetition. I wanted the numbers not to look too random so someone would think to try ASCII decoding them. I made sure that typing the first few words into Google would get you to the answer. Even with a knowledge tag, it's not fair to expect people to recognize the beginning of random Shakespeare sonnets.
I was prepared to offer up a couple of hints if people didn't think to Google. I planned to reveal that the agency was called Absolutely Secret Counter Intelligence, Inc. to clue ASCII. I had some clues to suggest the boss was a Shakespeare fan. In the end these were not needed but it's good to think about hints beforehand.
This was all about Google: making sure the sonnets were readily available online, making sure there were no alternate numberings. The ASCII charts are readily available with hex, octal, and decimal numbers.
Your thoughts/mental process
I really didn't think this was going to work very well. I went at the whole process the wrong way around. I had a puzzle with everything except a puzzle. I think it would be very easy to go very wrong with this sort of thing. I'm glad people seemed to like it in the end. If I thought it would be so popular, I would have spent more time on it. Possibly without making it any better.
Edit. Tighten it up. If your puzzle involves a story or a poem, make them as good as possible but don't waste the reader's time. Use whatever tools you have. Humour helps.