Overview

Codna understands a repository before it acts. It maps the code for about zero model tokens, then fixes, reviews and secures from the evidence. Runs on your machine or your cloud.

Agents read your code. Codna understands it.

Codna maps your repository deterministically before it spends a model token. It hands the agent the evidence for this issue, not the whole tree, and reports the bundle size on every run. Point it at a local checkout or a git URL.

New to Codna? Start with the Quickstart: install, add a model key, triage a repository, and open your first fix PR.

Start here

Quickstart

Install, add a key, triage, and open a fix PR.

Installation

One pip command. No Node, Bun, Docker, or engine.

CLI Reference

Every command, argument, and flag.

Choose an outcome

Fix a failing test

codna fix finds the root cause and opens a pull request you review.

Review every pull request

codna review posts findings with severity, category and confidence, and approves a clean diff.

Prove a scanner finding

codna secure reads SARIF and proves which findings are reachable, for zero model tokens.

Connect Codna

GitHub App

Reviews pull requests when they open, answers @codna review, and opens fixes on request.

GitHub Action

thyn-ai/codna-action@v1: fix, review or secure from your own CI.

MCP Server

Five tools for Cursor, Claude Desktop, or your own agent.

Understand and explore

How It Works

Snapshots, evidence bundles, blast radius, and the reduction ratio.

Privacy and data

What leaves your machine, and what never does.

Configuration

Environment variables and the codna.yaml file.

Hooks

Lifecycle scripts that can observe, annotate or block an agent turn.

Troubleshooting

Every message and its one-line fix.

What Codna does

You run one command, codna. Everything it needs ships inside the package. There is no server to start.

Capability	Command	What it does	Model tokens
Understand	codna triage	Maps the repository and locates the code relevant to an issue. Deterministic.	0
Fix	codna fix	Finds the root cause and plans a patch. With --apply it writes a local branch; with --open-pr it opens a pull request. Every fix reports root cause, impacted symbols, confidence and blast radius.	On the patch
Review	codna review	Reviews a pull request read-only. Posts findings with severity, category and confidence. Approves a clean diff.	On the review
Secure	codna secure	Reads SARIF from CodeQL, Semgrep, Snyk or Trivy and proves which findings are reachable.	0 to classify
Test selection	codna impact	Prints the tests a diff can affect. Offline.	0
Code memory	codna_recall (MCP), codna memory export	On-device recall of the symbols relevant to a query.	0
Report	codna report	Files a bug, request or question to thyn-ai/feedback.	0

The GitHub App and the GitHub Action run the same codna commands you run on your machine. A review posted by the App, by the Action, or by codna review --post reads the same way.

Install

pip install codna

No Node, Bun, Docker, or engine to install or start. Python 3.12 to 3.13 on macOS or Linux, with git on your PATH.

For pipx, uv, optional extras and offline use, see Installation. For keys and model selection, see Models & BYOK.

A first look

Point Codna at a directory to understand it. Triage spends no model tokens.

codna triage .

The values below show the format. Codna prints the measured values for your repository.

codna: understanding . …

✓ codna understood 412 files in 1.8s
  suspect files : src/checkout/total.py, src/checkout/cart.py
  context        : 1,840,000 → 9,400 tokens  (196× smaller for the agent)

Then fix a bug. Without --apply or --open-pr, fix reports its analysis and a patch reference and changes nothing.

codna fix . --issue "tests/test_checkout.py::test_total returns the pre-tax amount"

codna: fixing . …

✓ codna analyzed .
  root cause   : total() sums line items but never applies the tax_rate field
  symbol       : checkout.total.compute_total  (blast radius: 3)
  confidence   : 91%
  context      : 1,840,000 → 9,400 tokens  (196× smaller)
  agent        : repository.verified_agentic_v1 via codna  ·  cost: $0.021
  patch        : $PATCH_REF   (--apply for a local branch · --open-pr to open a PR)

Next: the Quickstart walks install, triage, fix and PR end to end. The CLI Reference documents every command.

Community

Questions or feedback? File them with codna report, or join us on Discord. Security reports go to [email protected] and are acknowledged within two business days.