koment

Keep the why next to your code — checked, so it can't quietly rot.

The problem

Someone wrote retry 5 times instead of 3, and there was a good reason. Six months later nobody remembers it, so it gets "simplified" back to 3 and the bug returns.

A comment was supposed to prevent that. Comments rot: they sit next to the code without being attached to it, and when the code changes nothing tells you the comment just became a lie. Your AI agent then reads that lie and acts on it.

What koment does

You record the reason outside the source, anchored to the exact lines it explains. Then koment watches those lines. Change them, and it says so:

$ koment check
internal/auth/token.go
  drifted   gotcha        internal/auth/token.go  01KZN63VC5SZASDYJBMPDC03WB
    Without it, clients whose clock runs fast get logged out mid-request. Bit
    us in #412.
1 annotation across 1 file: 1 drifted
koment: 1 annotation no longer resolves; revisit it or update the anchor

Exit code 1. The build stops. Nobody silently inherits a reason that no longer describes the code.

The records are YAML in .koment/, in your git repository. No database, no service, no account. They review in the same pull request as the change that motivated them.

See it running → — koment's own annotations, published by a workflow you can copy.

For AI agents

This is where it earns its keep. Agents write explanatory comments constantly, and they edit code without reading why it was written that way. koment makes both of those fail immediately, while the agent is still working:

• It writes a comment → the edit is refused, with instructions to record the reasoning as an annotation instead.
• It edits annotated code without checking → the turn cannot finish until the annotation is revisited.

One MCP server serves Claude Code, Cursor, Codex, opencode, Hermes, Zed and the rest, so every agent reads the same reasoning through the same interface. Set yours up →

Humans get the same loop in the editor: a squiggle under the comment, and a quick fix offering convert to annotation or keep it, on the record.

Install

brew install koment-dev/tap/koment

mise use -g github:koment-dev/koment          # mise
go install github.com/koment-dev/koment/cmd/koment@latest
docker run --rm -v "$PWD:/repo" -w /repo ghcr.io/koment-dev/koment:3 check

Try it in a minute

From inside any git repository:

koment bootstrap

That sets up .koment/ and wires whichever agents you use. Now record a reason and watch it get checked:

koment add src/auth.go \
  --excerpt 'if token.Expiry.Before(now.Add(-clockSkew)) {' \
  --kind gotcha \
  --title 'Skew subtraction keeps fast clocks logged in' \
  --body 'Without it, clients whose clock runs fast get logged out
          mid-request. Bit us in #412.'

koment check     # ok

Now edit that line and run koment check again. It fails, and tells you which reasoning no longer matches its code. That is the entire product; the rest is delivering it to the people and agents who need it.

koment ui        # read them in a browser
koment show src/auth.go

How it works

1. You annotate a snippet. koment records the prose, exact excerpt, surrounding source context, the commit you were on, and who you are.

2. The record lands in .koment/annotations/<id>.yaml, one file per annotation. Concurrent agents create independent files instead of replacing one shared list.

3. Resolution searches the current file for that excerpt and produces exactly one status:

   	meaning	build
   ok	found where it was last seen	passes
   ambiguous	several contextual candidates remain	fails
   drifted	file exists, the annotated code is gone	fails
   orphaned	the file is gone	fails

4. koment check exits non-zero on ambiguous, drifted or orphaned. That is the whole mechanism: uncertain rationale is worse than no annotation, so it has to be impossible to ignore.

5. When it fails, koment reanchor <id> --excerpt '<new text>' repoints it — keeping its id and creation date, recapturing context and the line for you. Nothing re-attaches automatically; a person confirms the reasoning still holds.

Anchoring is by excerpt, never by line number — line numbers rot on the next edit above them. The commit hash is recorded, but only to reconstruct history; it never decides whether an annotation still applies. Those are two different questions with two different mechanisms.

Local writes change the checkout you are already reviewing. Served writes never touch a replica or push a default branch: they create an exact annotation on a deterministic branch and return only after its pull request exists. Static publications remain immutable and read-only.

Three ways to run it

Pick one. Each is a place to stop, not a step you have to take, and moving between them is not a migration — all three read the same .koment/ in git, so there is nothing to export, import or back up.

Several repositories

One deployment serves many. Identity is assigned independently of provider path, and every refresh resolves a branch to one immutable commit before replacing a repository's active snapshot:

# yaml-language-server: $schema=https://raw.githubusercontent.com/koment-dev/koment/main/schema/server.schema.json
repositories:
  - id: payments
    name: Payments API
    provider: github
    remote: you/payments
    default_branch: main
    default: true
  - id: web
    name: Customer Web
    provider: github
    remote: you/web
    default_branch: main

The service starts only when a non-loopback listener has either trusted-proxy identity or scoped bearer credentials. Private repositories and reviewed writes also require a GitHub token. The Helm chart documentation shows the secret formats and boundary.

Local commands need none of this configuration — koment finds the owning checkout by walking up from the working directory.

Kubernetes

koment publishes an OCI Helm chart to oci://ghcr.io/koment-dev/charts/koment:

helm install koment oci://ghcr.io/koment-dev/charts/koment \
  --set repositories[0].remote=you/your-repo \
  --set metrics.enabled=true \
  --set metrics.serviceMonitor.enabled=true \
  --set metrics.dashboard.enabled=true

The application port authenticates source, rationale, UI and MCP; only liveness and readiness are public. Metrics use a separate listener so an ingress cannot accidentally expose them with application authentication. The chart includes a Grafana dashboard, ServiceMonitor, hardened pod defaults, optional NetworkPolicy and disruption controls, and a digest-pinned helm test probe.

Configuration

Every flag can be set from the environment. --flag-name becomes KOMENT_FLAG_NAME, and an explicit flag always wins.

Git is the only authoritative record. Local reads resolve the YAML directly against the working tree; disposable read models cannot restore or overwrite Git.

koment <command> --help lists every flag alongside its variable.

Work where the code lives