clay-borg/workplans/CB-WP-0019-the-am4-family.md

---
id: CB-WP-0019
kind: meta
title: "Budgets: what the meta budget is for, AM-4b's scope, and the self-quoting rule"
status: todo
---

# Purpose

```
structural tier  M   (changes how the loop constrains its own operation:
                      a budget's scope and target, and a reporting rule)
chaos            d8 = 5  → no override
declared tier    M
```

Declaration 2 of chaos window 2, and **the first roll at d8**.

**Meta budget is 0%** over the trailing three, all product. ADR-0006 D2
exempts instrument repair anyway, and this is the repair four evidence
files have listed as owed.

## Two numbers that have been owed for five passes

Both were measured before this declaration, so the work is scoped against
facts rather than an intention to find them.

**AM-4b's scope**, owed since CB-EV-0012 §3:

| | crates | lines |
|---|---:|---:|
| AM-4b as instrumented (`games-ground`, `--edges normal`) | 29 | 317,021 |
| the whole workspace, dev edges included | 57 | 725,258 |
| **uncounted** | **28** | **408,237** |

**The dev-toolchain budget is blind to more source than its own target
of 350,000.** `criterion`, `clap`, `ciborium`, `quick-js` and now
`cb-game-runtime`'s dev graph are all invisible to it.

**AM-4b's proc-macro share**, owed since ADR-0008 D2: **109,585 lines,
15.1%** of the real graph.

That 15.1% is worth stating plainly, because it **vindicates a decision
made for the right reason**. ADR-0008 D2 refused to correct AM-4b using
AM-4a's measured 36.2%, saying *"correcting a second instrument on the
strength of the first one's ratio is the error this change exists to
fix."* The shares are 36.2% and 15.1%. Borrowing would have been wrong by
a factor of more than two.

## Task: give AM-4b a scope, and a target that matches it

```task
id: CB-WP-0019-T01
status: todo
priority: high
```

Decide what AM-4b is **for**, then instrument that.

The two honest candidates, and the choice needs an argument rather than a
default:

- **Widen it** to the whole workspace with dev edges — everything a
  contributor's `cargo test` acquires. Then the target must move with the
  instrument, exactly as ADR-0008 D3 moved AM-4a's, and **the target moves
  to fit the measurement, not the measurement to fit the target.**
- **Narrow the claim** to what it actually measures and rename it, if
  "one package's non-dev graph" is the thing worth bounding.

Whichever wins, **do not repeat ADR-0008 D3's generosity by reflex.** That
decision gave back a small rounding-up because a target with 1.5% of room
fails on a patch release; a target set 130% above the current reading
would not be a budget at all.

**Controls:**
- the mutation must still go red — AM-4b's row is currently enforced and
  must stay so;
- a test that the configuration measures what its name says: if it claims
  dev edges, a dev-only dependency must move the number. `quick-js` is the
  case to use, because it is dev-only and it is what exposed this.

## Task: the proc-macro share, decided not just measured

```task
id: CB-WP-0019-T02
status: todo
priority: high
```

15.1% is measured. What is owed is the **decision**: does the dev budget
exclude proc-macro crates as the shipped one does?

The shipped case was easy — a proc-macro never reaches a shipped binary,
so counting it in "what a game ships" was simply wrong. **The dev case is
not the same question.** A proc-macro *is* acquired, *is* compiled, *is*
unaudited third-party source on a contributor's machine, and the
acquisition rule (ADR-0007 D3) counts what the build causes to be fetched.

So the arguments point opposite ways and the answer is not inherited.
Decide it, and say which of the two rules governs when they disagree.

**Whatever is decided, ADR-0008 D2's note that AM-4b's share is unmeasured
must stop being true in the source.**

## Task: write the self-quoting rule down

```task
id: CB-WP-0019-T03
status: todo
priority: high
```

Six passes, six under-reports, both halves of the defect diagnosed, and
the rule still lives only in evidence files:

| pass | reported mid-flight | settled | under by |
|---|---|---|---|
| CB-WP-0009 | $6.73 | $11.31 | 40% |
| CB-WP-0011 | $4.23 | $7.02 | 40% |
| CB-WP-0012 | $8.82 | $14.52 | 39% |
| CB-WP-0013 | $5.78 | $8.26 | 30% |
| CB-WP-0015 | $15.14 | $22.70 | 33% |
| CB-WP-0017 | $5.19 | $9.48 | 45% |

**Six for six, always low, never by less than 30%.** That is not noise;
it is a systematic bias with two identified causes (CB-EV-0013 §5,
CB-EV-0015 §6):

1. a pass's window runs to the **next** pass's first commit, so the
   previous pass is not final until the one after it starts;
2. **a figure read earlier in a session is an in-flight figure regardless
   of whose name is on it** — quoting from memory defeats the rule even
   when the boundary is right.

Put it in `specs/InnerLoop.md` as a rule with both halves, and make
`loop-lint` check what it can. A rule that lives only in prose has been
re-derived three times already.

**The honest question to answer while writing it:** is the right rule
"quote two passes back", or "re-run the instrument at quote time", or
both? T03 of CB-WP-0018 used the second and it worked. Say which is load
bearing.

## Task: say what the meta budget is *for*, and set it at 80/20

```task
id: CB-WP-0019-T05
status: todo
priority: high
```

The maintainer, 2026-08-03:

> *"we should establish a rule for what the budget is for. The main budget
> should be spent on the task at hand while some of the budget should be
> spent on control, review and improvement of the process we use to propell
> us forward. We can make that 80/20 to start with and allow for increasing
> or lowering the meta budget based on the phase or task at hand."*

META-25 has a threshold and **no stated purpose** — which is why it has
been argued about as a number three times. Write the purpose first; the
number follows from it.

### The window and the ratio have to be chosen together

The budget is measured over a **trailing 3-pass window**. One meta pass
among three, at the same cost as its neighbours, is already **33%**. So a
20% soft line over three passes does not mean *"one pass in five is
meta"* — it means *"one in five **and** at half the cost of a product
pass"*, which pushes meta work toward being rushed rather than rare.

| window | what a 20% line requires of a meta pass |
|---|---|
| trailing 3 | costs **half** a product pass |
| **trailing 5** | costs **the same** as a product pass |

**80/20 over a trailing 5-pass window is the literal reading of the
instruction:** one pass in five, at normal cost. Adopt that, and say in the
spec that the ratio and the window are a pair — changing one without the
other changes what the rule means.

### The phase dial, and why it must not be a dial

*"increasing or lowering based on the phase or task at hand"* is right —
stage 0 and a stabilisation phase should not carry the same ratio. But a
threshold anyone may move is not a threshold, and this project has a
standing rule that a limit is fixed structurally rather than raised
(four loadability breaches, `make status`'s 40 lines).

So the phase setting must be **declared, argued, and expiring**, in the
same shape `gates.toml` already uses: a value, a reason, a `review_by`
after which it reverts to 20 unless re-argued. Raising it silently to pass
a breach is the failure this shape exists to prevent.

**Controls:** `status.py`'s self-test must cover the new window and ratio,
and must fail if a phase override has no reason or no expiry.

## Task: evidence

```task
id: CB-WP-0019-T04
status: todo
priority: high
```

`evidence/CB-EV-0017-*.md`.

- **The AM-4 family, closed or not.** Four defects found across five
  passes, none by looking for them. State whether any remain and whether
  the family is now trustworthy — and if a fifth is plausible, say where.
- **What five passes of being "owed" cost.** These two numbers were
  carried as open items in four consecutive evidence files. Either the
  carrying was cheap and correct, or it was a way of not doing the work;
  say which, with the cost.
- **Quote CB-WP-0018's cost by re-running the instrument.** Under the rule
  T03 writes down.
- **The meta budget's new shape**, and what it would have said about the
  last five passes had it been in force. If 80/20 over trailing-5 would
  have failed passes that were plainly right to run, say so — that is the
  ratio being wrong, not the passes.
- **Chaos: declaration 2 of 12 in window 2, first roll at d8.**