Learn Review

Reviews facts in workspace/learning/facts/ whose next_review date is today or in the past. Applies SM-2 grading and rewrites frontmatter in-place. Records every grade in workspace/learning/.state/review-log.jsonl.

SM-2 Formula (implement exactly as specified)

Given current reps, interval, ease, lapses:

Again (grade 0):

• reps = 0
• interval = 1
• ease = max(1.3, ease - 0.2) (round to 2 decimal places)
• lapses = lapses + 1

Hard (grade 3):

• interval = round(interval * 1.2) (minimum 1)
• ease = max(1.3, ease - 0.15) (round to 2 decimal places)
• reps = reps + 1

Good (grade 4):

• If reps == 0: interval = 1
• Else if reps == 1: interval = 6
• Else: interval = round(interval * ease) (minimum 1)
• ease is unchanged
• reps = reps + 1

Easy (grade 5):

• Same interval as Good, then additionally: interval = round(interval * 1.3) (minimum 1)
• ease = ease + 0.15 (round to 2 decimal places)
• reps = reps + 1

For all grades: next_review = review_date + interval days

Ease floor: 1.3. Never let ease drop below 1.3 regardless of how many Again grades.

Workflow

Step 1 — Scan for due facts

1. Read all .md files in workspace/learning/facts/
2. Parse the frontmatter of each file
3. Get today's date (YYYY-MM-DD)
4. Select facts where next_review <= today
5. Sort by next_review ascending (oldest due first)
6. Take up to 5 facts (N=5 default)

If no facts are due:

"Nenhum fato vencido hoje. 🎉 Próxima revisão: {earliest next_review across all facts}." Stop here.

If workspace/learning/facts/ does not exist or is empty:

"Nenhum fato encontrado. Use /learn-capture para adicionar fatos primeiro." Stop here.

Step 2 — Review loop (one fact at a time)

For each due fact (up to 5):

2a. Show the question:

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📚 Deck: {deck} | Fato {current}/{total_due_shown}
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❓ {Retrieval Q content}

[Pense na resposta antes de prosseguir. Pressione Enter quando pronto.]

Wait for the user to confirm they've thought about it (any input is fine).

2b. Show the answer:

✅ Resposta:
{Fact content}

💡 Por quê importa:
{Why it matters content}

2c. Ask for grade:

Como foi? 
  0 - Again  (errei / não lembrei)
  3 - Hard   (lembrei com dificuldade)
  4 - Good   (lembrei bem)
  5 - Easy   (muito fácil)

Wait for the user to enter 0, 3, 4, or 5. Accept also the words "again", "hard", "good", "easy" (case-insensitive).

Step 3 — Apply SM-2 and update file

For the grade received:

1. Compute prev_interval = current interval
2. Compute prev_ease = current ease
3. Apply SM-2 formula above to get new_interval, new_ease, new_reps, new_lapses
4. Compute new_next_review = today + new_interval days
5. Rewrite the fact file with updated frontmatter, preserving the body content exactly

Frontmatter rewrite rules:

• Update only: next_review, interval, ease, reps, lapses
• Preserve all other fields unchanged: id, source, deck, created
• Preserve the body (everything after the closing ---) exactly as-is

Step 4 — Append to review log

Append one JSON line to workspace/learning/.state/review-log.jsonl (create file if it doesn't exist, create directory if needed):

{"ts": "{ISO8601_timestamp}", "fact_id": "{id}", "grade": "{again|hard|good|easy}", "prev_interval": {N}, "new_interval": {M}, "prev_ease": {X}, "new_ease": {Y}}

Grade string mapping: 0→"again", 3→"hard", 4→"good", 5→"easy"

Step 5 — Next fact

Continue with the next due fact. After all N facts (or all due facts if < N):

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✅ Sessão de revisão concluída!
Revisados: {N} fatos
Resultado: {X} Good/Easy | {Y} Hard | {Z} Again
Próxima revisão: {earliest next_review across all facts}
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Verification helper (Grade Good progression)

When testing, the interval sequence for repeated Good grades starting from reps=0, interval=1, ease=2.5:

Constraints

• Max N=5 facts per session. If more are due, the user can run again.
• ONLY update files in workspace/learning/facts/ and workspace/learning/.state/review-log.jsonl.
• Do NOT modify deck metadata files or any file outside these two locations.
• Do NOT skip the log write — even if the user types a grade quickly, always append to the log.
• If a fact file cannot be read (corrupted frontmatter), skip it and report: "⚠ Fato {filename} ignorado — frontmatter inválido."