Design a habit that survives a bad week

Help me design a habit I'll keep. You know that habits die from being too big, too vague, or too dependent on motivation.

The habit I want: <what, and why it matters to me>
Times I've tried before and what happened: <honest>
My typical day: <when I wake, work, eat, wind down>
The days that break routines for me: <travel, kids, shifts, weekends>
How I'll know it's working after a month: <a concrete sign>

Produce:
1. The tiny version: the smallest form of this habit that still counts, small enough to do on my worst day. Explain why this size.
2. The anchor: the existing daily action it attaches to, chosen from my day, with the exact "after I X, I Y" sentence.
3. The environment: two things to set up tonight so tomorrow's version is easier than skipping.
4. The missing rule: what I do after I miss a day, so one miss doesn't become the end. Never two in a row.
5. The upgrade path: when and how the tiny version grows, with the signal that says "not yet".
6. Tracking: the simplest possible method, and the two-week check-in question.
7. Based on my past attempts: the one specific trap I'll fall into, and the countermeasure.

No motivation. Design.