Pre-order open — ships June 2026
// septim witness · agent decision audit log

Every choice your agent made, written down.

Witness records every significant decision a Claude Code session makes during a build — which file it touched, what it reasoned, where it got stuck — so on the next build you have a durable trail instead of reconstructing it from git blame.

Claim founding rate — $79 → See what it logs ↓

founding rate, first 10 ship at $79 — regular price $99 after that.

// the cost you're not tracking

The March 2026 cache-nerf made this urgent.

Anthropic's March 2026 1-hour cache regression cut effective cache windows for long Claude Code sessions. Developers running multi-file builds started seeing token burns they couldn't account for — the session had reasoned something through 40 minutes ago but by the time it touched file #12, that context was gone and it burned tokens re-reasoning it.

Witness solves the downstream problem: even when the cache breaks, you keep the record. The log survives. The next session reads it cold and spends zero tokens re-discovering what the last one already figured out.

// what witness captures

Three streams. One durable log.

Witness attaches to a Claude Code session and writes a structured audit trail as the session runs. No external service. Your Anthropic key. The log stays on your machine.

01 · decisions

Every significant choice

Which file the agent chose to edit first, which it deferred, and the stated reasoning — captured as a timestamped entry so you can replay the session's mental model.

02 · file touches

Full file-touch timeline

Every read, write, and skip logged with the agent's reason. When git blame gives you a cryptic diff, the Witness log tells you what the agent was trying to fix when it made that change.

03 · token ledger

Real-time token accounting

Logs every token spent per session, per agent, per file, in real time. After the March cache regression, knowing where tokens actually went stopped being optional.

04 · stuck points

Where the agent stalled

Witness flags when a session circled the same file more than twice without writing — a reliable signal that the agent hit a dead end it didn't surface to you.

// sample log output

09:14:02  SESSION_START   scope: refactor auth module  0 tok
09:14:04  FILE_READ       src/auth/session.ts           2,140 tok
09:14:09  DECISION        will touch middleware first; session.ts depends on it
09:14:11  FILE_READ       src/middleware/index.ts        1,830 tok
09:14:19  FILE_WRITE      src/middleware/index.ts        3,210 tok
09:14:24  STUCK           src/auth/token.ts — read 3×, no write
09:14:31  DECISION        token.ts type mismatch; deferring to next pass
09:15:44  SESSION_END     files written: 3  skipped: 1   18,440 tok total
// who reads the log

Built for solo builders who use Claude Code seriously.

If you're running Claude Code sessions long enough to forget what happened at the start, Witness is for you.

  • Solo founders running multi-day Claude Code builds where context resets between sessions and costs real tokens to reconstruct.
  • Developers whose agent sessions touch 10+ files and need to know which decision caused which downstream diff.
  • Anyone who looked at git blame after a Claude session and had no idea why the agent made the change it made.
  • Teams running parallel sub-agents where each agent's reasoning trail needs to stay legible to the next one.
  • Builders who got burned by the March 2026 cache regression and want a session record that survives it.
// founding rate

Pay once. You keep it.

Witness is a private GitHub repo invite, a CLI script that attaches to your Claude Code sessions, and a log format spec. No subscription, no telemetry, your Anthropic key. The first 10 pre-orders ship at $79; after that the price goes to $99.

founding rate — first 10
$79
$99
pay once, you keep it — ships June 2026
Includes: private GitHub repo invite · CLI attacher script · log format spec · lifetime updates as the format evolves · no subscription, no telemetry, your Anthropic key

Drop your email and I'll send you the pre-order link directly — with a Stripe checkout, your name on the founding list, and the repo invite the day it ships.

Or email directly: [email protected] · I reply same day.

// questions

FAQ

Is this available now?
Not yet. Witness is in final build — ships June 2026. Pre-ordering now locks the founding rate at $79 and puts your name on the repo-invite list. You pay when Stripe checkout goes live; I'll email you the link the week it ships.
What exactly do I get?
A private GitHub repo invite containing the Witness CLI script, the log format spec, and example parsers. The script attaches to a Claude Code session process and writes structured .witness.log files to your project root. No cloud sync. The log stays local unless you push it.
Does this use its own API key or mine?
Yours. Witness reads the same ANTHROPIC_API_KEY environment variable your Claude Code session uses. It observes the session's output stream — it does not make separate API calls, so it adds zero token cost on top of your normal usage.
What does "lifetime updates" mean for a $79 product?
The log format spec will evolve as Claude Code's output format changes (Anthropic has changed it three times in the past 12 months). Founding-rate buyers get every update pushed to the same private repo — no re-purchasing. The repo invite is permanent.
What if it's not right for my workflow?
Full refund within 14 days of the ship date, no questions asked. Email [email protected].
Does it work with the March 2026 cache regression?
That's exactly why this exists. When the 1-hour cache window cuts out, Witness ensures you still have a readable record of what the session decided before the context expired. The next session reads the .witness.log file directly — a cold read costs a fraction of what it costs to re-derive the same reasoning from source.
// lock the founding rate

First 10. Then $99.

Reserve now, pay when the Stripe link goes live in June. private GitHub repo invite ships the same day.

Reserve founding rate →

no subscription, no telemetry, your Anthropic key — pay once, yours forever