30 — Composed Stacks: Conservative / Aggressive / Unbelievable

This file does the end-to-end dollar math. Savings are composed per token class, sequentially (multipliers on the class a technique actually touches) — never by multiplying headline percentages across different classes.

TL;DR

• The defaults already bank the first ~4–5x. Prompt caching (−86.3% input-side, measured live), MCP schema deferral, Edit-tool diffs, and 1h-TTL main-loop caching are Claude Code defaults in 2026 — the baseline this dossier optimizes is already the optimized world of 2024-era folklore. Most "easy 10x" claims are unknowingly re-selling the defaults.
• Conservative stack (T1/T2, zero quality risk, Claude-Code-today): 1.06x main-loop, up to ~1.3x on fan-out days. The honest number nobody markets: with good defaults, riskless config-level wins are small.
• Aggressive stack (adds T3 + SDK tier + validation plans): ≈2.5x ($21.83 → ~$8.6/day on the modeled profile), led by effort-tiering, model routing at task boundaries, context editing, and register compression.
• Unbelievable stack (everything defensible incl. BUILDABLE frontier): ≈5–6.2x at the modeled profile; a paper path to ~10x exists only by making Sonnet the main loop with frontier-model escalation — quality parity there is unproven (T4), so 10x is NOT defensible at zero quality loss today.
• Binding constraints, in order: (1) frontier-model thinking output — no API lever except effort touches it; (2) the cache-read floor of context the agent genuinely uses; (3) quality risk of cheap-model main loops on the hardest tasks.

0. Baseline and composition rules

Working profile (01-economics-and-measurement.md §5, $22 variant = 6 × measured session):

Composition rules: a technique is a multiplier on one or two classes; sequential application (order shown); cross-class couplings carried explicitly (shorter outputs → slower transcript growth → smaller future R; context clears → extra W). Every multiplier cites its source file. Sensitivity: the $17/45%-thinking floor profile shifts totals ~−22% but does not change any ratio (same multipliers).

What the baseline already includes (do not double-count as savings): prompt caching (13: measured −86.3% input-side vs uncached equivalent — $71.59 paid vs $524.23 on this very session), MCP deferral by default (12), Edit-tool default (15), 1h-TTL main-loop writes (13: 320/320 calls observed), prior-turn thinking billed per current docs (18).

1. Conservative stack — "do this tomorrow"

Constraints: T1/T2 evidence only, CLAUDE-CODE-TODAY only, zero quality risk (each item is NEGATIVE-COST or NEUTRAL with a trivial falsification check).

Main-loop total: −$1.23/day → 1.06x. With routine subagent fan-outs: up to ~1.3x. Failure modes of the composition: none interacting — items touch disjoint behavior. Validation: 31-validation-harness.md screening run (n=12) once; C1's falsifier is the failed-old_string retry rate, C2's is cache_read_input_tokens continuity across turns.

The honest conservative headline: riskless knobs are small because the platform already turned the big ones. The conservative stack's real value is not regressing (a busted cache or a restored 50k MCP schema load silently costs more than C1–C5 save).

2. Aggressive stack — adds T3 + SDK tier, validation attached

Adds: effort tiering, model routing, context editing/masking, register compression, batch. Each item carries a validation plan; adopt sequentially, validating each (the multipliers below are mid-range of the cited evidence, not best-case).

Sequential composition from $21.83:

Total ≈ $8.6–9.1/day → ≈2.4–2.5x (range = prose-heavy vs code-heavy routing plus A2 prose-share and A3 clear-frequency sensitivity).

Composition failure modes (watch these, they are real):

• A1 × A2 double-press terseness — effort-medium already produces terse output; adding the register can cross the token-complexity cliff on hard tasks (15 §10). Canaries C1–C6 of the harness are mandatory after stacking both.
• A3 × caching — every clear invalidates the prefix at the clearing point (18); clear_at_least must exceed the re-write cost (the W×1.10 above models this; verify applied_edits vs cache_creation in usage).
• A4 × caching — the prompt cache is model-scoped; route only at session/task boundaries (16: mid-session switch ≈ 9-turn break-even).
• A5 — batch is for genuinely latency-tolerant work only; misrouting interactive work to batch costs wall-clock, not dollars.

Validation: full harness confirmation run (n=30) on the composed stack as a unit, plus the effort-sweep experiment (15 §1) before and after A1 — it doubles as the missing thinking-fraction-by-effort measurement.

3. Unbelievable stack — chasing 10x

Adds BUILDABLE frontier items (20-frontier-ideas.md) and flips the main loop. Stated honestly: the quality side of U1 is the unproven hinge.

Composed (same sequential method, from the corrected Aggressive endpoint $8.63, prose-heavy case): U1 widens the routed share from half to ~all sessions (remaining Fable spend only on escalations): ≈ ×0.55 → $4.75; U2 ≈ ×0.93 → $4.42; U3 (R component) ≈ −$0.45 → $3.97; U4 ≈ −$0.10 → $3.87; U6 ≈ ×0.93 → ≈ $3.60/day → 6.1x against the $21.83 baseline (code-heavy endpoint ≈5.7x).

The paper path to 10x stretches U1 to a Haiku-drafting fleet with frontier verification and near-zero interactive frontier use (~$2.2/day). Every individual mechanism is shipped (T1); the composition's quality at parity is unmeasured (T4) — and 15 §10's token-complexity cliff plus 16's "agent teams ≈ 7x tokens" warn that cheap-model fleets can pay back their savings in retries and verification passes.

Verdict on 10x: not defensible at zero quality loss today. Defensible today: ≈2.5x with validation (Aggressive; ≈2.4x code-heavy), ≈5–6.2x if the routing flip passes your harness on your task mix. Binding constraint #1 is frontier-model thinking output ($4.46/day baseline — untouchable except by effort and by not-being-the-frontier-model); #2 is the cache-read floor of context the agent truly needs (R after A3/U3 ≈ $3.0/day is mostly useful context); #3 is quality risk concentration — every remaining big multiplier moves work off the frontier model.

4. The negative-cost set (save tokens AND improve output)

Explicitly identified across the dossier (the brief's "genuinely unbelievable" category):

Common thread: less junk in, less junk out — the input-architecture layer is where saving money and raising quality are the same action. Register compression is conspicuously not in this set (it is paid for in readability and caveat-risk), and that is the dossier's central correction to the operator's starting intuition.

Verification ledger