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liftoscript

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Write idiomatic Liftoscript code for weightlifting programs. Use when creating or editing program files in programs/builtin/.

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Source SKILL.md: https://github.com/astashov/liftosaur/blob/HEAD/.claude/skills/liftoscript/SKILL.md

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Write Liftoscript Program

Write a Liftoscript program for: $ARGUMENTS

Before writing any code, read these reference files:

  1. llms/liftoscript.md — full language reference
  2. llms/liftoscript_examples.md — complete program examples
  3. llms/exercises.md — built-in exercise list (always prefer built-in exercises)
  4. src/models/builtinPrograms.ts — valid values for frontmatter fields
  5. Browse programs/builtin/ for format and quality reference

Idiomatic Liftoscript Patterns

Templates are the foundation

Define templates with used: none once, then reuse everywhere with ...templateName. This is the #1 pattern for DRY code.

cluster / used: none / 4x6 / 67% / 60s / progress: custom(increment: 5lb) {~
  if (completedReps >= reps && week == 6) {
    rm1 += state.increment
  }
~}

Bench Press[1-6] / ...cluster
Squat[1-6] / ...cluster / progress: custom(increment: 10lb) { ...cluster }

Key rules:

  • used: none only needs to be declared once per template (in Week 1). Do NOT repeat it when redefining the template in later weeks.
  • Templates can have arbitrary names — they don't need to match an exercise.
  • Override specific parts (progress, weight, timer) on the reusing exercise while inheriting everything else.

Repeat exercises with [1-N], define only in Week 1

Exercises that appear every week should use [fromWeek-toWeek] syntax and only be written out in Week 1. Later weeks only redefine templates:

# Week 1
## Day 1
t1 / used: none / 3x5 / 75% / progress: lp(5lb)
Squat[1-4] / ...t1
Bench Press[1-4] / ...t1

## Day 2
Deadlift[1-4] / ...t1

# Week 2
## Day 1
t1 / 3x4 / 80%
## Day 2

# Week 3
## Day 1
t1 / 3x3 / 85%
## Day 2

Critical: Empty ## Day headers are REQUIRED in later weeks for repeated exercises to show up. Without them, those days won't exist.

Week range syntax [from-to]

Exercise[1-6] means the exercise repeats from week 1 through week 6. Exercise[5-6] means it starts from week 5 and runs through week 6 — useful for exercises that replace others partway through a program.

CRITICAL: [1,3,5] is NOT week selection. Comma-separated numbers in brackets are parsed as forced display ordering, not "only on these weeks." [1,3,5] means "forced order position 1, weeks 3-5." If you need an exercise on non-contiguous weeks (e.g., weeks 1, 3, and 5 only), you must define it explicitly in each of those week headers — there is no shorthand for non-contiguous weeks.

Forced ordering (Exercise[1,1-6]) is usually unnecessary. Use Exercise[1-6] unless you have multiple exercises starting on different days/weeks that need explicit ordering. The first number is a forced display order — only add it when the order would be ambiguous.

Supersets

Use superset: A where A is an identifier shared across exercises in the same group. The scope is per-day, so you can reuse the same label across different days:

Bench Press[1-6] / ...cluster / superset: A
Squat[1-6] / ...cluster / superset: A
Pull Up[1-6] / ...cluster / superset: A

Pre-exhaust supersets (isolation → compound with truly zero rest, e.g., Mike Mentzer's Heavy Duty): set 0s timer on the first exercise and warmup: none on the second. The default superset rest is 15s (enough to move between equipment), but pre-exhaust requires absolutely no recovery time. The second exercise skips warmup since the muscles are already warm from the isolation.

Chest Fly / 1x6 / 20lb 0s / superset: chest / progress: dp(5lb, 6, 10)
Incline Bench Press / 1x6 / 95lb / warmup: none / superset: chest / progress: dp(5lb, 6, 10)

Progression patterns

Linear progression — simplest, for beginners:

Squat / 3x5 / 135lb / progress: lp(5lb)

Double progression — increase reps in range, then bump weight. NEVER use rep ranges in set notation with dp():

Bench Press / 3x8 / 135lb / progress: dp(5lb, 8, 12)   // correct
Bench Press / 3x8-12 / progress: dp(5lb, 8, 12)         // WRONG

Custom progression — for percentage-based or block programs. Use rm1 += to preserve percentage relationships:

main / used: none / 1x5 58%, 1x5 67%, 1x5+ 76% / progress: custom(increment: 5lb) {~
  if (completedReps >= reps && week == 3) {
    rm1 += state.increment
  }
~}

Reusing progress logic with different parameters:

Squat[1-3] / ...main
Bench Press[1-3] / ...main / progress: custom(increment: 5lb) { ...main }

When reusing, only specify state variables that differ from the template. Omitted variables inherit the template's values.

Percentage-based programs

Use rm1 += state.increment (not weights +=) so that all percentage-based sets adjust proportionally. The weights += approach breaks percentage relationships.

Week/day guards in custom progress

Progress is defined once per exercise/label combination and fires after every workout day that has that exercise. In a 4-day program, the progress fires 4 times per week. Use week and dayInWeek to control WHEN it fires:

// Fire only on the last day of the last week in a 6-week block
if (completedReps >= reps && dayInWeek == 3 && week == 6) {
  rm1 += state.increment
}

CRITICAL: weights += applies to ALL weeks and ALL days by default (wildcard target [*:*:*:*]). In multi-day programs, you MUST guard with dayInWeek to prevent the increment from firing multiple times per week:

// WRONG — fires 4 times per week, adding 4x the increment
if (week == 1) { weights += 10lb }

// CORRECT — fires only on the last day of each week
if (week == 1 && dayInWeek == 4) { weights += 10lb }

This applies to any weights += in a progress block where the exercise appears on multiple days per week.

Warmups

  • Default warmups are auto-added. Use warmup: none for bodyweight exercises (Pull Up, Chin Up, Dip, etc.) or exercises where warmups don't make sense.
  • Custom warmups: warmup: 1x5 45lb, 1x3 135lb, 1x1 80% (percentages are of first working set, not 1RM).

Set variations (stage-based progression)

Separate set schemes with / and switch between them via setVariationIndex:

t1 / used: none / 4x3, 1x3+ / 5x2, 1x2+ / 9x1, 1x1+ / 75% / progress: custom() {~
  if (completedReps >= reps) {
    weights = completedWeights[ns] + 5lb
  } else {
    setVariationIndex += 1
  }
~}

Exercise variations (progression ladders)

Switch the movement itself (not the set scheme) by listing exercises separated by | and advancing exerciseVariationIndex. Useful for calisthenics ladders (r/bodyweightfitness RR). The current movement is marked with ! (first is current by default); exerciseVariationIndex is 1-based and wraps mod length.

Split Squat | Bulgarian Split Squat | Pistol Squat / 3x8 / progress: custom() {~
  if (completedReps >= reps) {
    exerciseVariationIndex += 1
  }
~}
  • Sets/reps/weights/progress are SHARED across variations - only the movement changes. Combine with set variations for a per-movement scheme. %/RPE resolve against the current variation's own 1RM.
  • A multi-variation exercise CANNOT be a reuse target (move shared sets into a used: none template); it CAN be a reuse consumer. The label comes from the first variation only.

Starting weights

  • If the program uses 1RM percentages, use % notation: 3x5 / 75%
  • If the program uses RPE, use @ notation: 3x5 @8
  • Otherwise, ALWAYS set a default starting weight: 3x8 / 135lb. Look up sensible defaults from startingWeightLb in src/models/exercise.ts.
  • Non-default equipment: startingWeightLb is calibrated for the default equipment (e.g., Shrug defaults to dumbbell at 45lb, Bicep Curl defaults to dumbbell at 20lb). When using a non-default variant like Shrug, Barbell or Bicep Curl, Barbell, always specify an explicit starting weight since the default will be wrong (e.g., Shrug, Barbell / 1x6 / 135lb).

Labels for same exercise with different roles

If the same exercise appears in different contexts (e.g., heavy and light), use labels:

power: Bench Press / 3x3 / 85% / progress: dp(5lb, 3, 5)
hyper: Bench Press / 3x10 / 60% / progress: dp(5lb, 10, 15)

AMRAP sets

Add + after the rep count: 4x3, 1x3+. The last set becomes as-many-reps-as-possible.

Ask weight

Add + after a weight to prompt the user to confirm: 3x8 100lb+. To ask for weight when none is explicit (e.g. inferred from RPE), use ?+:

Squat / 3x8 @8 ?+

Rest times

Specify per-exercise or per-set: 3x5 / 120s or 1x5 60s, 3x5 120s.

Validation

After writing, ALWAYS validate:

TS_NODE_TRANSPILE_ONLY=1 npx ts-node scripts/validate_liftoscript.ts programs/builtin/<id>.md

Use validation output to sanity-check:

  • Workout duration — does it match claims in the description?
  • Weekly volume per muscle group — any glaring gaps to mention in pros/cons?

Fix errors and re-validate until it passes.

Common Mistakes

  1. Repeating used: none on template redefinitions in later weeks
  2. Missing empty ## Day headers in later weeks (exercises won't appear)
  3. Using weights += in percentage-based programs (use rm1 += instead)
  4. Using rep ranges with dp(): 3x8-12 / dp(...) is WRONG
  5. Using [1,3,5] thinking it selects weeks 1, 3, and 5 — it's actually forced ordering, not week selection. For non-contiguous weeks, define the exercise explicitly in each week header.
  6. Adding forced order numbers when not needed: [1,1-6] vs [1-6]
  7. Forgetting warmup: none on bodyweight exercises
  8. Defining exercises in every week instead of using [1-N] and template redefinitions
  9. Using weights += without dayInWeek guard in multi-day programs — it fires once per day, so weights += 10lb on a 4-day program adds 40lb per week instead of 10lb
  10. Omitting rest timers from template overrides in later weeks — rest timers are NOT inherited across weeks. If the initial template defines / 120s, every week override must also include / 120s or the timer will be lost for that week.