yield-audit

한국어 문서 | English documentation.

Your CI dashboard says commits are up 40% since the AI rollout. yield-audit tells you that 22% of that output was reworked within two weeks — and that the rework rate on AI-marked commits is 1.7x the human rate.

yield-audit is a local, read-only CLI that crosses your AI coding agent's session transcripts with your git history and reports what actually survived: output survival rate, waste cost bounds, retry tax, cost per accepted task, cache locality, verification gaps, and AI-vs-human rework rates. Where usage tools (ccusage et al.) show the bill, yield-audit shows what the tokens left behind.

• Fully local — transcripts and git history are read; there is no networking code in the package at all.
• Read-only & deterministic — nothing is written to your repositories; --now pins a run for reproducibility.
• Zero runtime dependencies — Python ≥ 3.10 stdlib + the git CLI.
• Vendor-neutral — scans Claude Code (~/.claude/projects) and Codex CLI (~/.codex/sessions) transcripts; more adapters via a registry.

Quick start

# install (PyPI)
python3 -m pip install yield-audit      # or: uv tool install yield-audit
# one-shot, no install:
uvx yield-audit audit --repo /path/to/your/repo

# audit a repository (auto-scans every installed agent's transcripts)
yield-audit audit --repo /path/to/your/repo

# one vendor only
yield-audit audit --repo . --agent codex

# JSON / markdown reports
yield-audit audit --repo . --format json --details
yield-audit audit --repo . --format markdown > yield-report.md

# AI-transition comparison: two windows split at your rollout date
yield-audit aidd --repo . --split 2026-03-01 --days 90

# session timelines as a Perfetto trace (optional extra)
pip install 'yield-audit[perfetto]'
yield-audit export --perfetto --repo . --out trace.perfetto.json

# pre-warm the blame/tree cache (cron-friendly)
yield-audit snapshot --repo .

# environment check (git, transcript roots, session discovery)
yield-audit doctor --repo /path/to/your/repo

# export the session timeline as a Perfetto trace (optional extra)
python3 -m pip install 'yield-audit[perfetto]'
yield-audit export --perfetto --repo . --out session.perfetto.json
# then drag the file into https://ui.perfetto.dev (parsed locally, never uploaded)

Requirements: Python >= 3.10, git. No runtime dependencies. No network calls. (export --perfetto pulls in agent2perfetto only when you install the extra.)

Time windows (and how they interact)

A repeat audit reuses blame/tree results from ~/.cache/yield-audit (content-addressed by git SHA — it can never change an output, only how fast it arrives; --no-cache opts out, YIELD_AUDIT_CACHE_DIR relocates).

Sample output

$ yield-audit audit --repo .
input: 3 sessions, 10 api calls, 4 commits (1 attributed, 3 unclaimed)

== M1 output survival ==
overall survival: 54.2% of 24 added lines (pending units: 0)
  source     50.0%  (5/10 lines)
  test      100.0%  (6/6 lines)
  docs        0.0%  (0/4 lines)
  config     50.0%  (2/4 lines)

== M2 waste cost (bounds) ==
lower $0.00 — upper $0.00
  (session cost x attribution-share-weighted line-share proxy x waste class ...)

== M3 retry tax ==
tax tokens: 240 / 4000 (6.0%)
  [claude:bbbbbbbb] 2 attempts, 2 errors: npm test

== M8 verification gap ==
gap rate (never verified): 0.0% | strict (not verified before last commit): 0.0%

== M11 AI rework ==
reworked within 14d, by cohort (evidence-graded, not verdicts):
  certain    60.0%  (6/10 lines, 0 pending)
  probable   45.8%  (11/24 lines, 0 pending)
  human       0.0%  (0/13 lines, 1 pending)
  AI combined 50.0% vs human 0.0%  (evidence: certain=1, human=2, probable=1)

Lenses (v0.1–v0.3)

Honesty contract

• Every metric carries a measurement label: observed (read straight from transcripts/git) / estimate (observed × list price) / proxy (a stated stand-in, e.g. line-share standing in for per-commit token share).
• Attribution (session↔commit matching) is probabilistic, so every dependent number inherits confidence grades (high = the session ran the commit / medium = file & time overlap) and contested commits are split and flagged.
• Editing is not waste: <50% line loss is classified as iteration and counted in neither bound.
• No savings claims. Measurement only; intervention features stay behind a v1.x evidence gate.

Privacy

• Transcripts and git history are read only. Nothing leaves your machine — the package contains no networking code.
• Report paths are redacted to basenames by default; absolute and ~/ paths inside commands become <path> (--show-paths to undo). Windows UNC paths in free text are a documented gap.
• Every transcript-derived string (session ids included) is stripped of ANSI/C0/C1 control characters before it reaches a report, and the finished report is deep-sanitized recursively — no format can touch your terminal.
• git subprocesses run with GIT_* environment variables removed, so a stray GIT_DIR in your shell cannot redirect the audit.
• Session ids are truncated to 8 characters in reports.

Methodology & limits

• Survival: git blame --porcelain at a snapshot taken horizon-days after the commit; lines a later commit rewrote or deleted did not survive. Renames/copies are not followed in v0.1 — a renamed file counts as deleted.
• Token attribution: transcripts have no per-commit tokens, so session cost is split across commits by line share (labeled proxy).
• Commit attribution: edited-files ∩ commit-files × time proximity (default 24h, --proximity-hours). Pair programming and manual commits grade lower or stay unattributed. Contested commits split evenly and are flagged.
• Scale: survival/rework blame cost is linear in commits × files; a touch-map prefilter skips files no later commit changed, so a hundred-commit full-history audit runs in well under a second.
• Pricing: published list prices 2026-09 (Anthropic + OpenAI standard tier) built into pricing.py; override with --pricing-file; unknown models get a conservative top-tier price and are flagged.
• M8 correlations are observations, not causation. Small session counts prove nothing.

Roadmap

• v0.2 — ✅ shipped: vendor adapter registry (Claude Code + Codex CLI, --agent), namespaced session ids. Gemini lands once its schema is grounded.
• v0.3 — ✅ M11 AI rework rate shipped (cohorts certain/probable/human, --rework-days). Remaining: M12 settle rate (blame snapshots), M13/M14 (external CI data).
• v0.4 — ✅ aidd transition report shipped: two windows split at a rollout date, AI-vs-human rework cohorts per period (--split, --days), plus a persistent content-addressed cache and Codex transcript pruning.
• v0.5 — ✅ M12 settle rate (--settle-days) and M14 incident-origin cohorts shipped, plus snapshot (cache pre-warming) and a Perfetto export (export --perfetto, optional extra). M13 (verification-tax transfer) stays deferred: it needs external CI data, which the local-only contract forbids until an explicit opt-in design exists.
• v1.x — intervention layer (retry early-abort hooks, deterministic oracle routing) — each behind its own evidence gate.

Development

git clone https://github.com/ictechgy/yield-audit && cd yield-audit
python3 -m pip install -e '.[dev]'   # or: uv pip install -e '.[dev]'
pytest                               # tests (fixed-date fixture git repo)
ruff check .                         # lint

Contributions: lens logic must stay pure functions, and every new metric needs a measurement label plus a golden test. If you contribute via an AI agent, AGENTS.md takes precedence over the general guidance here. Adding a transcript vendor is one TranscriptAdapter subclass plus a registry entry — see src/yield_audit/transcripts/.

License

Apache-2.0. Methodological roots: arXiv:2601.16809 (survival analysis of AI-generated code) and the fully-loaded-cost-per-success perspective.