---
title: "Cache frontier weekly review - 2026-06-29"
description: "First recurring review entry for fak's cache-frontier operating plan, derived from the current cache-value ledger and demo surfaces."
---

# Cache frontier weekly review - 2026-06-29

This is the first dated review entry for the
[cache frontier operating plan](../README.md). It records what the current tree proves
today, without promoting thin evidence into a bigger claim. The matching machine row is
in [`review-ledger.jsonl`](../review-ledger.jsonl) under schema
`fak-cache-frontier-review/1`.

## Evidence run

Commands run from the repo root on 2026-06-29:

```bash
go run ./cmd/fak nightrun score --json
go run ./cmd/fak cachevalue report --since 2026-06-22 --json
go run ./cmd/fak cachevalue review --since 2026-06-22 --date 2026-06-29 --source-markdown reviews/2026-06-29.md --json
```

The `cache-savings` Track 2 ledger was absent, so the provider-dollar track is empty.

## 1. What did we use ourselves this week?

Track 1 has real WITNESSED kernel reuse, but the corpus is still thin and not yet the
full dev-loop dogfood target.

| Field | Current value |
|---|---:|
| Total cache-value sessions | 5 |
| Multi-turn sessions | 1 |
| Single-turn sessions | 4 |
| Total turns | 9 |
| Multi-turn turns | 5 |
| Prompt tokens | 457 |
| Reused tokens | 260 |
| Gate prompt tokens | 413 |
| Gate reused tokens | 260 |
| Realized reuse ratio | 0.6295399515738499 |
| Session type mix | `run`: 5 |

Read this narrowly: fak has a measured reuse signal from real `fak run` sessions, not
yet sustained `guard` / `serve` dogfood from the coding loop. The current weekly bucket
is marked `thin: true`; the reuse number is visible, but it is not yet trend-strong.

## 2. What can a new person demo this week?

The cache-frontier demo path is now one walkthrough:

```bash
go run ./cmd/ctxdemo -bars
go run ./cmd/turntaxdemo -print
go run ./cmd/ctxplandemo -selfcheck
go run ./cmd/memqdemo
go run ./cmd/unseedemo -print
fak nightrun score --json
```

The walkthrough is documented in
[run-the-demos.md](../../run-the-demos.md#cache-frontier-walkthrough). Its job is to
make the multi-agent reuse win, O(1) planned context, queryable memory algebra, and
addressable KV removal visible as one product story.

## 3. What is the next missing witness or product surface?

| Gap | Evidence | Next action |
|---|---|---|
| Thin Track 1 corpus | `multi_turn_sessions=1`, `multi_turn_turns=5`, weekly bucket `thin=true` | Accumulate more multi-turn `guard` / `serve` sessions, not only `run` rows. |
| No dev-loop dogfood rows | `session_type_mix={"run":5}` and no `guard` / `serve` rows | Capture multi-turn `guard` / `serve` cache-value rows from the dev loop. |
| No Track 2 provider-dollar row | `track2_observed_usd=[]`, no `docs/nightrun/cache-savings.jsonl` | Wire the OBSERVED provider-dollar append so `fak cachevalue report` can show real net dollars side by side with Track 1. |
| Multi-agent win still not dogfooded as a recurring geometry | Current cache-value rows are `run`, not a recorded 50-turn x 5-agent dogfood shape | Add a recurring multi-agent dogfood run or review entry that states the geometry and why it matches or differs from the benchmark. |
| O(1) query not yet our own agent memory workflow | Demo path exists, but the review did not query a real fak session image | Pick the first operator-facing query path and use it on a real repo session. |

## Verdict

Cache-frontier visibility improved: there is now a named operating plan, a local demo
walkthrough, and a first dated review entry with real cache ledger evidence.

The product goal is not done. The next review must move from thin `run` evidence to
dev-loop dogfood: `guard` / `serve` rows, Track 2 OBSERVED-dollar rows, and an O(1)
query over a real fak session.
