Token-saving-defaults scorecard — is fak’s out-of-the-box token economy amazing?
The question a cost-conscious operator asks the moment they run fak guard -- claude / fak serve: of every token-saving method fak knows how to stack, which ones are ON by default — and are the high-value, low-loss ones turned on out of the box, or left dark behind a flag nobody flips? Every number below is re-derived from the entrypoint source (cmd/fak/guard.go, cmd/fak/serve.go, the Default* constants in internal/gateway/gateway.go, and internal/gateway/messages.go) by fak token-defaults-scorecard — a lever’s on/off state is the binary’s real behavior, never a claim in the roster. The headline metric is token-defaults-debt: the count of concrete defects — a high-value saver left off, an on-by-default saver with no honest note, a default no test locks, a front door out of step. Driving it to zero means a user who runs fak with no flags gets the full stack of safe savings, each honestly labeled, none able to regress unnoticed.
Budget size is governed separately by the long-context defaults doctrine: the advertised context window is a hard cap, not a target, and resident budgets should be labeled as witnessed, observed, modeled, or fallback.
Regenerate:
go run ./cmd/fak token-defaults-scorecard --markdown > docs/serving/token-defaults-scorecard.md
Headline
| Metric | Value |
|---|---|
| Token-defaults-debt (total HARD defects) | 0 |
| Composite score | 100.0/100 (grade A) |
| Savers stacked on by default | 7/7 |
| Groups | stack 100 · honesty 100 · regression 100 · parity 100 |
| Advisory (soft) signals | 0 |
Per-lever status — where each token-saving method stands
class: lossless = zero model-visible change (must be on); bounded = lossy but an in-code guard keeps the model’s working set intact (high-value → should be on, with a note); optin = broader blast radius (correctly off, must carry a documented gate). gated = an off lever documents why; noted = an on bounded lever documents what it sheds + cache-safety; locked = a test pins the default.
| Lever | Class | Default | Witness | Blocker | Flag | Gated | Noted | Locked |
|---|---|---|---|---|---|---|---|---|
| provider_cache — provider prompt-cache prefix (byte-faithful passthrough) | lossless | ON | ✓ | — | (structural) |
· | ✓ | ✓ |
| toolfloor — tool-floor pruning (drop provably-unreachable tool defs) | lossless | ON | ✓ | — | (structural) |
· | ✓ | ✓ |
| vdso — vDSO dedup fast path (collapse identical calls) | lossless | ON | ✓ | — | --vdso |
· | ✓ | ✓ |
| compacthistory — history compaction (drop the un-cacheable middle past the budget) | bounded | ON | ✓ | — | --compact-history-budget |
· | ✓ | ✓ |
| elideresult — oversized-result elision (shrink a scrolled-past tool_result to head+tail) | bounded | ON | ✓ | — | --elide-result-bytes |
· | ✓ | ✓ |
| elidestale — stale-read elision (replace a Read superseded by a later same-file edit with a restorable marker) | bounded | ON | ✓ | — | --elide-stale-reads |
· | ✓ | ✓ |
| ctxview — ctxplan O(1) planned view (re-materialize history under a budget) | bounded | ON | ✓ | — | --ctx-view-budget |
· | ✓ | ✓ |
KPIs
| Group | KPI | Score | Debt | Detail |
|---|---|---|---|---|
| stack | stacking_depth |
100 | 0 | 7/7 token-saving methods stacked on by default out of the box |
| stack | lossless_stack |
100 | 0 | 3/3 lossless savers on by default |
| stack | high_value_defaults |
100 | 0 | 4/4 demonstrably-safe bounded-loss savers on by default |
| honesty | witness_status |
100 | 0 | no off-by-default high-value savers remain — every bounded-loss saver defaults on |
| honesty | dark_lever_gated |
100 | 0 | 0/0 off-by-default levers carry a documented gate |
| honesty | default_notes |
100 | 0 | 4/4 on-by-default bounded savers carry an honest loss note |
| regression | default_on_locked |
100 | 0 | 7/7 on-by-default savers pinned by a regression sentinel |
| parity | entrypoint_parity |
100 | 0 | front doors agree + servewiring verdicts track the real defaults |
Token-defaults-debt work-list
No token-defaults-debt: every stacking saver fak can safely default is on out of the box, honestly noted, and locked against regression. 🎉