Say what you want done.
Keep it as a file.

Checked before it runs. Run with the model you choose. Proven afterwards.
Nika turns the AI work you repeat into a readable workflow that stays yours.

_{“Read my invoices. Ignore rejected ones. Sum by customer. Pay only after I approve.”
▶ The 30-second film, with sound (MP4) · an illustration with fixture data, not a recording: the program it draws passes the real check, and the film notes say what is real and what is illustrated.}

What is Nika?

Nika turns repeatable AI work into a small file you keep. Say what you want done, like "every Monday, pull the action items out of my meeting notes", and Nika writes it as a readable .nika workflow. Before anything runs, its check shows what the workflow will do, which models and tools it uses, what it is allowed to touch and what it can cost, without calling a model. You run it when you decide, with the model you choose, local or cloud, and every run leaves a tamper-evident record you can verify. One Rust binary, local-first, open source (AGPL-3.0).

See it · Control · Try it · Examples · Why a file · Where it works · Limits · Docs

See it in four steps

1 · Say it

Describe the job in plain words. Nika writes it as a .nika file, shows you what it will do and what it can touch, and saves it only when you say yes. Nothing runs until you ask.

_{One sentence becomes a checked file; yes saves it, run it keeps the two paid rows, and /proof shows what the run recorded. The real Session, restyled; no AI model involved.}

2 · Check it

Before anything runs, nika check reads the file and reports what it will do, what it may touch and what it can cost. It calls no model and spends nothing.

_{Two mistakes caught before anything runs, the fix, and the clean re-check. Every line is captured from the real CLI.}

3 · Run it

You run it when you decide, with the model you choose. Here a local model, through Ollama, writes a meeting's action items as typed JSON.

_{The audit first, then a real run on a local model (ollama/llama3.2:3b). Nothing leaves the machine.}

4 · Prove it

Every run leaves a hash-chained record. nika trace verify reads it back, and when a single byte changes it names the line where the chain breaks.

_{The chain read back intact, then one changed byte refused at the next line. A mock/echo rehearsal captured from the real CLI; the scan is an illustration.}

You stay in control

It tells you the cost before the first token

nika check prices a workflow from its model's catalog price and the output limit each step declares. Set a budget below that ceiling and the run refuses to start: no model is called and nothing is spent.

_{Unbounded until one line declares max_tokens, then a hard ceiling of $0.0614; a $0.05 budget refuses the run (exit 2). Prices are catalog estimates, not invoices; no model was called.}

It asks before it acts

A step can wait for a person. At your terminal it asks; in CI, where nobody can answer, the run pauses safely with exit 4 and prints the one line that resumes it.

_{Nothing ships without a yes: asked at a terminal, paused in CI, resumed by the printed line with the finished build reused. Every terminal line is captured from the real CLI; the door is an illustration.}

Try it in two minutes

1 · Install

curl -LsSf https://nika.sh/install.sh | sh

2 · Say what you want

This first job needs no AI account: Nika's deterministic compiler settles it without calling a model. Make a folder with a small spreadsheet and open the Session:

mkdir -p orders-demo/data && cd orders-demo
cat > data/orders.csv <<'EOF'
order_id,customer,status,amount
1001,Juniper Books,paid,18.00
1002,Kestrel Cafe,pending,9.50
1003,Linden Studio,paid,13.50
1004,Moss Supply,refunded,6.00
EOF
nika

At the prompt, type:

Read ./data/orders.csv, keep only the rows whose status is paid, and write them to ./out/paid.csv.

Nika proposes a .nika file and shows what it will do, what it can touch and the result of its check. Nothing has run yet. Type yes to save the file, then run it. out/paid.csv gets the header and the two paid rows, and /proof shows what the run's record proves, and what it does not.

[!TIP] Nika works only inside the folder you start it in. /show prints the proposal's exact bytes, /meaning maps your request clause by clause, and no discards it. Ctrl+T switches the view to full screen and back, and nika --plain gives the same Session as plain lines. The Session guide covers questions, changes, spending ceilings and /restore.

3 · Add a model

Most open-ended requests need a model to write the workflow, and workflows such as summaries call a model each time they run. Nika reads provider keys from your environment, so keep yours in your shell startup file. For DeepSeek:

# in ~/.zshrc or ~/.bashrc, then open a new terminal
export DEEPSEEK_API_KEY='your-key'

The first request that needs a model shows a numbered choice: answer 2 deepseek/deepseek-flash. Nika keeps the choice for later Sessions, and /intelligence changes it. Other API providers and local engines (Ollama, llama.cpp, LM Studio, vLLM) work too: nika catalog lists them. Your provider meters and bills these calls; Nika's cost figures are catalog estimates, not invoices.

4 · Use the file directly

A workflow is an ordinary file. The command line compiles, checks, runs and verifies it. This offline lesson needs no provider:

nika compile hello hello.nika
nika check hello.nika
nika run hello.nika
nika trace verify

▶ Watch these four commands run, exactly as captured from the CLI.

hello always uses mock/echo, a stand-in model that echoes the prompt, even when provider keys are present. It proves that the workflow runs, not that a model answered. Each run records its trace under .nika/traces/, and creating the file adds that directory to .gitignore. nika trace verify checks the latest trace's integrity, not the truth of an AI answer.

What you can hand to Nika

Why a file, and not a chat?

A chat answer is gone when the conversation ends, and the next one can differ. A .nika file stays: you read it, check it, run it again and review its changes like any other file in your project.

• Say it once. The request you would retype in a chat every week is kept as a file that runs again. ▶ Watch a weekly request become a file
• Read it before it runs. Every workflow has the same shape: nine sections and four kinds of step, in a file you can open and review. ▶ Watch one taken apart
• It touches only what it declares. The file lists what it may read, write and reach. The check refuses the step that reaches past it. ▶ Watch the check catch an escape
• Failures are planned for. A step can name its fallback: the run finishes, the output says it is stale, and the record keeps the failure. ▶ Watch a missing feed absorbed
• Parallel where it can be. Steps that do not depend on each other run side by side, in waves the check plans before the run. ▶ Watch a workflow run in waves

Apart from the film at the top, an illustration with fixture data, every clip on this page shows real files and terminal lines captured from the binary, and names what it illustrates. The media index lists them all and how they are made.

Works where you already work

Nika comes to the tools you already use. Your coding agent can write the file for you, and the check keeps it honest:

_{Your agent writes it, Nika checks it, you keep it. The agent session is an illustration; the checks and the rehearsal run are captured from the real CLI.}

Know the limits

• Nika is pre-1.0. The Session was qualified on six synthetic tasks with one macOS installation of an identified development build, not the released binary (qualification note). That is not a general reliability claim.
• Some requests cannot be expressed yet. Nika then says what stopped it and writes nothing.
• A clean check is not a true answer. It describes a file's structure and boundary; it does not prove that model output is right.
• Public releases do not include a knowledge snapshot. Without one, authoring uses the language card built into the binary.
• This README follows the source tree. An older installed release may lack what it describes: compare nika --version with the changelog. What main carries beyond the latest release is described one file per change in changelog.d/.

nika compile --base workflow.nika --change 'Set const.topic to "new topic"' --json

🦋 The Nika family

This repository is the one executable: it parses, checks, runs and traces every workflow. The language is defined by the specification, and the other repositories drive this engine without adding to its authority.

Go further

Session guide · Examples · Documentation · TypeScript SDK · Editor extension · Open specification · Registry · Planning archive · Website

Nika is usable today and pre-1.0. The engine is AGPL-3.0-or-later; the specification is Apache-2.0.