An open-source skill for Claude Code
indelible runs your self-study the way a strict, kind tutor would. You read theory on a sheet and then close it. Claude marks your work from photos of your paper. Everything comes back cold two days later, and only what you still know then counts.
Your 2-day recheck is ready. Take it now
Install it in Claude Code
claude plugin marketplace add romanprigodskii/indelible
claude plugin install indelible@indelible
Then open Claude Code in an empty folder and say “set me up for…”, naming what you are learning. Needs Python 3.9 or later.
Not sure yet? Try a 2-minute sheet on this page and come back for the recheck.
These are the rules a good tutor holds you to. indelible keeps them in every session, including the days you would rather it didn’t.
Theory comes on its own sheet. You read it and put it away before the drills, because an explanation left in view turns a test into a lookup.
Drills come in blocks of one question type. Anything that measures you is shuffled and unlabelled, like the real exam.
Every new skill comes back cold two days later, on fresh problems. Same-day scores are practice.
Beside every answer you write one check that runs the other way. Solving it again in your head repeats the same slip. A written check catches it.
Each mistake goes in an error log and returns after 1 day, 3 days, 1 week and 3 weeks, until it stays.
You get the smallest hint that unblocks you, never an answer you could reach yourself. When an answer is wrong, you see where, and the fix is yours.
With the explanation in view, every answer is a lookup. It feels like knowing, and it isn’t.
So theory comes on its own sheet. You read it, close it, and only then get the drills. Reopening is allowed, but it is written down, and those answers count as practice.
Theory sheet
Sort the list, then take the value in the middle: 3, 9, 4, 12, 7 sorts to 3, 4, 7, 9, 12.
Add 100 to that list and the average jumps from 7 to 22.5. The middle number only moves to 8.
Even count: take the average of the two middle values.
Close this sheet now. The drills come separately.
Six in a row of one kind makes the step automatic.
But a real exam never says which topic a question is from. So anything that measures you is shuffled and unlabelled, and you have to recognise the problem before you can solve it.
Teaching block
Block A · the middle number
One kind, six in a row
Recheck
Sheet 07
Mixed, with no headings
This sheet is real. Answer each question, then write a check beside it that works backwards. It is marked when you hand it in.
Your answers stay in this browser. Nothing is sent anywhere.
Practice sheet
Write your answer. Then write one check that works backwards. The sheet is marked when you hand it in.
Same-day scores are practice. What counts is the 2-day recheck: fresh questions 44 to 72 hours later, with nothing looked at in the 24 hours before. Every miss then comes back after 1 day, 3 days, 1 week and 3 weeks.
Day 0 The lesson
You read the theory sheet, close it, and do the drills: 6 of 6.
Practice. It does not count yet.
Day 2 The 2-day recheck
Fresh numbers, nothing looked at in the 24 hours before, book closed. 3 of 4.
This one counts. The miss goes on the ladder.
Day 3 +1 day
The miss comes back, after the idea behind it has been fixed.
Passed. Next in 3 days.
Day 6 +3 days
Again, cold, mixed in with other topics.
Passed. Next in a week.
Day 13 +1 week
Again, with no heading to say which topic it is.
Passed. Next in 3 weeks.
Day 34 +3 weeks
The last rung: four passes on four different days.
Retired. It stayed.
These are indelible’s default intervals, not measured results. You can change them.
These are four of the questions indelible asks when you set it up. Change the answers and the plan follows its rules: a diagnostic before any teaching, and a protected recheck 44 to 72 hours after every lesson. Click a session to mark it missed.
Claude, at your next session
A preview in your browser. Nothing here is saved or sent anywhere, and no real calendar is touched.
A short interview, one question at a time, each with a default: your goal and date, where you are now, your materials, session length and days, when your head is clearest, when you sleep.
You see a two-week plan first and the calendar question second. Nothing is written until you say yes to a one-screen summary. Then a diagnostic, before any teaching.
(6 of 8) How long should a normal session be (15–20, 30, 45, 60, 90, or 120–150 min), and on how many days a week?
> 60 minutes, four days, never more than 90
Your first two weeks: IELTS · ~4 h/week · 60-min sessions · exam 12 Dec
Week 1 Week 2 Mon 07:00 Diagnostic, part A New skill + 2-day recheck Tue 07:00 Diagnostic, part B + results rest Thu 07:00 First skill: sheet, closed 2-day recheck + fixed mistakes Sat 10:00 2-day recheck + second skill Timed section
Want these in your calendar? I found Google Calendar.
| Claude Code | Supported, in the terminal, the desktop app and the IDE extensions. |
|---|---|
| Cowork | Should work with a shared folder. Untested in v0.1. |
| claude.ai chat and mobile | Not yet: files don’t persist between chats there. A limited manual mode is offered instead. |
A skill cannot physically stop the model from breaking its own rules, so the rules that matter most do not rely on instructions alone. The only route to a printable sheet runs a sheet checker. The only route to an answer key needs your attempt filed first. The next session finds anything the last one skipped, and does it first.
The method was developed with one learner over about four weeks. That is not a controlled study. The principles come from well-studied effects: retrieval practice (Roediger & Karpicke, 2006), spacing (Cepeda et al., 2006) and interleaving (Rohrer & Taylor, 2007). The numbers, like 48 hours and six questions a block, are defaults you can change.
Two commands in Claude Code. Then say “set me up for…” and answer a few questions.
claude plugin marketplace add romanprigodskii/indelible
claude plugin install indelible@indelible
Or copy skills/indelible into ~/.claude/skills/.