fsi — FSI Language Drill Skill

/fsi

Five minutes a day, inside the tool you already live in.
Your build is compiling. You just learned the French subjunctive.

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What and why `/fsi`

The FSI method (Foreign Service Institute) was developed by the U.S. State Department to train diplomats in foreign languages through high-repetition pattern drills — substitution, transformation, and contextual practice. It's one of the most effective approaches to building spoken fluency through structured repetition.

/fsi brings that method into your coding agent. Engineers won't open Duolingo between builds — but they'll type /fsi in the terminal they already have open. No app, no subscription, no streak anxiety.

One command. Thirty reps. Real progress — while CI does its thing.

What a session looks like

You: /fsi

French · A2 · Session 8

▶  Continue
   Switch language or level

→

You: (enter)

Je voudrais _____ s'il vous plaît.
I'd like _____ please.
[ʒə vudʁɛ]

Cue 1 → a window seat

You: Je voudrais une place côté fenêtre s'il vous plaît.

✓  Cue 2 → the menu

You: Je voudrais la carte s'il vous plaît.

✓  Cue 3 → a coffee

Stuck on a word? Type h for help — without breaking the drill:

Cue 4 → a seat near the window

You: h seat

  seat = une place / un siège

Cue 4 again → a seat near the window

...

[ʒə vudʁɛ] — stress on the last syllable, drops flat.
Cue 6 → something sparkling

...

↩ from last time → a room with a view

You: Je voudrais une chambre avec vue s'il vous plaît.

✓  Cue 8 → ...

After 20 correct substitutions, the drill shifts:

Now: transform the sentence.

Make it negative.

Cue 1 → Je voudrais une table pour deux.

You: Je ne voudrais pas de table pour deux.

✓  Cue 2 → Je voudrais le menu du déjeuner.

After 10 correct transformations:

You're at a café. The waiter is waiting.
Use today's phrase →

You: Bonjour, je voudrais un crème et un croissant s'il vous plaît.

✓

Done. 20 sub + 10 transform · Je voudrais · 3 errors

Quick Start

Claude Code

/plugin marketplace add phunterlau/fsi
/plugin install fsi@phunterlau/fsi

Then type /fsi in any session.

Gemini CLI

git clone https://github.com/phunterlau/fsi
gemini extensions install ./fsi

Any ACP-compatible agent

git clone https://github.com/phunterlau/fsi
# Point your agent at SKILL.md

How it works

Stage	What happens
Bootstrap	Reads `~/.fsi_practice/` session history — or detects first run
Onboarding	Pick a language (French / Spanish / German / other) and self-assess level with sample sentences
Substitution Drill	20 correct reps on a core chunk. IPA pronunciation guide, rhythm notes every 5 reps, SRS cues from past sessions injected at cue ~7 and ~14
Transformation Drill	10 correct reps. Same chunk, different structure — negation, tense shifts, passive voice, register changes (level-dependent)
Contextual Moment	One real-world scenario: use today's phrase to navigate a situation
Wrap-Up & Level Eval	Session saved. Level-up suggested after 3 clean sessions (≥90% accuracy + ≥80% SRS recall)

Session state persists in ~/.fsi_practice/ — every drill builds on the last.

Drill features

Feature	Description
Echo Method	IPA guide + out-loud repetition before typing
Substitution Drill	20 reps filling the core chunk with varied vocabulary
Transformation Drill	10 reps reshaping the sentence — negation, tense, voice, register
Rhythm Pauses	Pronunciation and intonation notes every 5 reps
Spaced Repetition	Review cues from previous sessions injected mid-drill
Blunt Feedback	"Wrong. Repeat:" — not paragraph-length corrections
`h` Help System	Type `h`, `h [word]`, `h pronunciation`, `h grammar` — one-line answers, cue repeats
Contextual Output	Every session ends with a real-world scenario at your level
Passive Level Eval	Tracks error rate and SRS recall across sessions
Level-Up Suggestions	Suggests moving up after 3 clean sessions — never suggests down

Transformation types by level

Level	What you practice
A1	Statement → question
A2	Affirmative → negative, present → near future
B1	Present → passé composé, direct → indirect speech
B2	Active → passive, concession (subjunctive), informal → formal
C1	Nominalization, formal inversion, modal shifts

Supported languages & levels

Language	Levels
French	A1 · A2 · B1 · B2 · C1
Spanish	A1 · A2 · B1 · B2
German	A1 · A2 · B1 · B2
Any other	Type it — the coach adapts

Recommended Models

Drills live or die by response latency — a slow coach breaks the rhythm. Use a fast, lightweight model:

Platform	Recommended Model
Claude Code	`claude-haiku-4-5-20251001`
Gemini CLI	`gemini-3.1-flash`

Both keep the drill snappy and the cost near zero. Avoid large reasoning models — speed is part of the drill.

Session files

All state is local. No accounts, no cloud sync.

~/.fsi_practice/
├── profile.json      # Language, level, session count, streak
├── history.json      # Per-session drill records
└── srs_bank.json     # Spaced repetition cue bank

OpenClaw / ACP

fsi is compatible with OpenClaw and any ACP-compatible agent runner. See AGENTS.md for the agent definition.

Changelog

1.0.0 — Initial release.