# Method traps already paid for

Each line cost an iteration at least once. They are general — they are not about
Sylpheed, they are about how this kind of measurement goes wrong.

Like [`REFUTED.md`](REFUTED.md), this list had been living in the autonomous
agent's loop prompt, i.e. nowhere durable. See [`README.md`](README.md) for the
✅/🟡/❔ confidence convention itself.

## Controls

* **Every result needs a control. A control that fails kills the instrument.**
* **Run the known-positive through a new filter FIRST.** Three filters have been
  killed by their own control. When one fails, **read the known-good's
  disassembly** before assuming a shape.
* **A measured negative is a result** — but a negative is only as strong as the
  route you ran, so **state its reach**.
* **A null result needs its cause shown to have happened.**
* **A result with NO unknowns is suspicious.**
* **Census the whole set; always run the other population as the control.**
  **Zero partials is stronger than a majority.**
* **A 2×2 partition is the sharpest general tool** — both off-diagonals empty is
  a law.
* **Re-derive a doc's own numbers as the control.**

## Inference

* **Never conclude from ONE sample.**
* **A law proved on one population is a hypothesis on the next.**
* **Finding one exception does not imply a family.**
* **Consistency is not proof. A suggestive coincidence is a coincidence until
  measured.** **An analogy is not a measurement.**
* **Same layout ≠ same instance.** **Same record-name set ≠ same object.**
* **A marker is only proven by what it leaves out.**
* **A high-confidence SCORE is not a high-confidence MECHANISM.**
* **Knowing HOW MANY is not knowing WHICH.**
* **Round numbers matching is weak evidence — unless you read the constant.**
* **My own last-turn result is a hypothesis too.**
* **A global partition can understate a per-owner one.**
* **A residual is measured against a population — name it.**

## Searching and tooling

* **A search that returns thousands has no power; state the reach.**
* **A substring match is not a hit.** **A regex miss looks like a null result —
  print one raw sample before believing a zero.**
* **A derived table can be a cross product — measure its shape first.**
* **After refuting an instrument, sweep everything that depended on it.**
* **Before measuring how wrong a tool is, read what the tool actually does.**
* **The instrument must pass its own control.**
* **Classify a bulk before mining it. The residual is the prize.**
* **Rank by similarity — the cliff is the finding.** But **read the values
  before trusting the rank.**
* **Grep the nouns before designing the experiment — and believe it.**
* **Grep gives you a file list — read *every* file on it.**
* **The answer is often already in the doc that owns the subject — read it end
  to end.** A 🟡 often names its own route.
* **Before re-trying a blocked idea, check whether the blocker's own doc already
  tried it.**
* **Ship a regenerator with every artefact.** An artefact that moves by a pure
  reorder is a tool bug.
* **Never print per-entry lines from a disc-wide sweep — aggregate.**

## Reading the data

* **Read what a loader NAMES, not where it stores.**
* **A field the disc never values still gets named by the loader.**
* **An indexed read beats a deduped-pool adjacency read.**
* **Check the whole string set, not the one matching word.**
* **A dict keyed by record name across a multi-entry pak is a lie.**
* **A set-difference over names hides reuse — join per USER.**
* **A self-index names records, not files.**
* **Case-insensitive hashing means two spellings can be one entry.**
* **An "unresolved" name may be the wrong kind, namespace or prefix — or part of
  a cut asset.**
* **A garbled value may be a real string in another encoding.**
* **Two of my own counts disagreeing is a grammar clue.**
* **A game's own typo is a join key.**
* **A bias constant in the code is a join key.**
* **A prefix trap: enumerate maximal `[A-Za-z0-9_]` runs, not `startswith`.**
* **Re-deriving a format is not a finding — asking whether its values *resolve*
  is.**

## Mechanics that have bitten

* **Never hand-convert a decimal VA — print `hex()`.**
* **`grep -c` counts LINES** — use `grep -o | wc -l`.
* **`Counter.most_common()` tie-breaks by insertion order — use `sorted()`.**
* **Raw grep cannot see inside compressed pak entries.**
* **Commit messages go in a file** (`git commit -F`); a literal `|` in a table
  cell needs escaping; `git log --all -- <path>` can hang.

## Runtime / emulator

* **Look at the PNG** — and check its dimensions.
* **"Animating" is not "still in a mission".**
* **Dedup entity enumerations by position value.**
* **Do not diagnose timing or liveness under gdb.** `ps %cpu` is cumulative.
* **Classify screens by whole-image statistics, not named pixels** — a named
  pixel is only valid while the image sits at a known place, and nothing errors
  when it moves.
* **Do not poll faster than the guest updates** — it manufactures a clean curve
  out of noise.
* **A probe that never performs the action will "prove" the action does not
  exist.**