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18 October 2026 5 min Members llamacpp context gpu audit

The 42 KB context audit

The reader was serving a quarter of the context the model was trained for, and the plan said there was nothing above it worth reaching for. One unit error, one constant, and 12 GB of headroom.

Labels. [MEASURED] — from the live endpoint, a receipt or the audit in the pack. [FACT] — a file you can check. [OPINION] — mine.

The audit is 42 KB: 684 lines, five findings, one recommendation, and a section titled “What I did not verify” [FACT, llamacpp-context-audit.md]. It exists because one number in the deployment looked wrong against another number in the code, and the gap between them was 4×.

The reader is a 35B model served by llama.cpp on an L40S. The live endpoint said:

field value
default_generation_settings.n_ctx 65,536 — per slot
total_slots 4
n_ctx_train 262,144
model Qwen3.6-35B-A3B, Q4_K_M, 20.4 GB

[MEASURED, the live /props and /v1/models]

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The proof pack — attachments

Included with the piece — 7 files, 73 KB. Sign in as a member to download.

  • Reader brief — audit your inference server’s context budget 00-reader-brief.md · 6.1 KB · sha256 255ded8b
  • The context arithmetic, in one page context-math.md · 2.7 KB · sha256 1a5ab0f4
  • Licence — personal use licence.md · 0.5 KB · sha256 cd1f7f1c
  • The full context audit (42 KB) llamacpp-context-audit.md · 39.9 KB · sha256 0900b0a9
  • The reader worker (metatron_reader.py) metatron_reader.py · 17.0 KB · sha256 1c2a26c7
  • The Modal runbook modal-readme.md · 5.9 KB · sha256 7ddae6ee
  • How to reproduce the audit reproduce.md · 1.2 KB · sha256 9ba53f6a