# Personality Council Run — LLM Inference Cost Reduction

**Topic**: Best approach to reduce LLM inference costs by 50% without quality loss?
**Mode**: Personality (Pragmatist / Visionary / Skeptic)
**Flow**: Parallel, 1 round
**Tier**: Light (all subagents on default model — Sonnet 4.6)
**Date**: 2026-03-05 19:32 UTC
**Subagent calls**: 4 (3 advisors parallel → 1 referee)

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## Advisor Perspectives

### Pragmatist

Two concrete steps hit 50% in under two months:

1. **Prompt caching (this week)**: Anthropic/OpenAI prefix caching. If system prompts are >1K tokens and reused frequently, cache hit rates of 70-90% are common. 20-35% cost reduction with zero quality impact.

2. **Query router (Q2)**: Routing layer sends simple/classification tasks to smaller models (GPT-4o-mini, Haiku, Llama-3-8B). Can handle 60-80% of traffic at 5-10x lower cost. 40-60% reduction with measurable quality parity on routed tasks.

3. **Self-hosting (later)**: Quantization + self-hosted inference for >$10K/month spend. 2-4 months to operationalize.

Math: Routing (40%) + Caching (25% on remainder) ≈ 55% total. Achievable in under 2 months.

Avoids: aggressive context truncation, speculative decoding alone, over-relying on fine-tuning.

### Visionary

"50% without quality loss" is the *wrong framing* — too conservative.

Highest-leverage bets:
1. **Speculative decoding at scale**: Smaller draft model proposes tokens for larger verifier. 2-3x throughput gains with zero quality degradation.
2. **Mixture-of-Experts routing**: Learned, task-aware, dynamic routing. Don't need all 70B parameters for every task.
3. **Hardware-native quantization**: INT4/INT8 with GPTQ/AWQ achieve near-parity on most benchmarks. Teams waiting for "perfect" quantization are leaving 40-60% savings on the table.
4. **Long game**: Neuromorphic/in-memory compute (IBM NorthPole) — 2-3 years to meaningful production deployment.

Recommendation: Don't optimize for 50% — architect for 10x by combining speculative decoding, dynamic MoE routing, and aggressive INT4 quantization now.

### Skeptic

"Without quality loss" is almost always a post-hoc rationalization, not a measured outcome.

Key failure modes:
1. **Tail-case invisibility**: Quantized/distilled models degrade on rare reasoning chains, novel instruction formats, edge-case domains — exactly where benchmarks don't measure and where it hurts most.
2. **Silent quality leaks from routing**: Routing classifiers are wrong some percentage of the time, and those errors are systematically invisible (you don't know what the bigger model would have said).
3. **Uneven compression**: Cost reduction hurts low-frequency, high-stakes requests more than high-frequency, low-stakes ones. If 5% of queries are what matters most, you can't see the damage in aggregate metrics.

Prompt/batching caching is the safest lever but savings vary wildly by workload (could be 10%, not 80%).

Recommendation: Measure quality on actual production distribution before and after any change, with specific focus on tail-case performance. Treat "without quality loss" as a hypothesis to falsify.

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## Referee Verdict

### Points of Agreement
- Routing by task complexity is legitimate — all three accept it, Skeptic just demands measurement rigor
- Prompt/KV caching is low-risk — closest thing to a free lunch
- Quantization has real tradeoffs — even Visionary says "near-parity," not parity
- Infrastructure complexity has a cost — none say "do everything at once"

### Key Tensions

1. **Optimize for now vs. architect for later**: Pragmatist wants 50% in two months; Visionary thinks that goal anchors you to a suboptimal architecture. Both have merit — near-term wins build trust and budget for larger bets.

2. **"Quality parity" as fact vs. hypothesis**: Sharpest disagreement. Pragmatist asserts it as measured outcome; Skeptic says it's usually measured on the wrong distribution (head cases, not tail). Skeptic is technically correct — most published routing quality results are on aggregated benchmarks.

3. **Benchmark claims vs. production reality**: Visionary cites research numbers; Skeptic notes controlled benchmarks don't reflect real traffic. Doesn't make Visionary wrong about direction, but implementation risk is higher than headlines suggest.

### Recommendation (sequenced)

1. **This week — Enable prompt caching.** Zero risk, 20-35% reduction. Just turn it on.
2. **Before building a router — instrument your production distribution.** Log a sample with model outputs, establish baseline including tail-case performance. 1-2 weeks. De-risks everything that follows.
3. **Q2 — Build query router with quality gates.** A/B test routing decisions, track tail performance separately from aggregate, define explicit rollback criteria. 40-50% additional reduction if quality holds.
4. **Longer term — adopt Visionary's framing selectively.** Speculative decoding and MoE worth piloting once measurement infrastructure exists. Revisit in 6-12 months.

The Pragmatist's sequence is the right spine — add the Skeptic's measurement layer before each step, not after.

### Confidence
Medium. Would shift if tail-case data revealed systematic quality degradation in routing — at that point, 50% target may require accepting some quality tradeoff.
