colibri/docs/ENVIRONMENT.md

Environment Variables

Reference for the environment variables read by the colibrì engine.

Generated from upstream/dev @ 6d3ed7e by scanning every getenv() site in c/glm.c. Defaults and behavior are taken from the source; see MAINTAINING-DOCS.md to regenerate this after the code changes.

Which program reads these?

The C engine binary (c/glm, built from c/glm.c) reads all of these. You rarely export them by hand — the coli CLI and openai_server.py translate most of their flags into these variables before launching glm (e.g. --temp → TEMP, --ctx → CTX). See SETTINGS.md for the flag → variable mapping. Export a variable directly only to reach a knob the CLI doesn't surface, or to override what the CLI would set.

Format: VAR — default — effect.

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Common — everyday use

Variable	Default	Effect
RAM_GB	0 (auto ≈ 88% of free RAM)	RAM budget in GB for the resident/streamed expert working set. Higher → more experts stay hot → higher cache hit rate.
CTX	4096	Maximum context length (tokens) the KV cache is sized for.
NGEN	256 (engine)	Max tokens to generate before stopping (stop tokens can end sooner). coli --ngen defaults to 1024.
TEMP	-1 (auto: 1.0 for chat/text, greedy elsewhere)	Sampling temperature. TEMP=0 = greedy/argmax = deterministic.
NUCLEUS	0.90	Nucleus (top-p) mass kept when sampling. Slightly tighter than the official 0.95 because the int4 tail is noisy.
TOPK	0 (off)	Top-k filter on the sampling distribution (0 = no limit).
TOPP	0 (off)	Top-p filter (0 = use NUCLEUS).
SEED	unset → seeded from clock + PID	RNG seed for sampling. Unset = different every run. Set a fixed value for reproducible sampling.
KVSAVE	1 (on)	Persist the KV cache to <model>/.coli_kv so a conversation reopens warm. KVSAVE=0 disables save+load (lossless round-trip; does not change output).
KV_SLOTS	1	Number of independent KV conversation slots (1–16), used in serve mode.
THINK	0 (off)	Emit a <think> reasoning block. THINK=1 turns on visible reasoning.
MTP	on	Multi-Token Prediction (speculative draft head). MTP=0 disables it.

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Performance / tuning

Variable	Default	Effect
COLI_METAL	off	Enable the Apple-Silicon Metal GPU backend. Requires a make METAL=1 build.
COLI_METAL_GEMM_MIN	16	Minimum matmul rows to dispatch a GEMM to the GPU (below this, stays on CPU).
COLI_METAL_SPIN	off	Keep a GPU keep-alive spinner running (reduces dispatch latency; costs power).
PIPE	0 (off)	Overlap expert disk-load with matmul via I/O worker threads. Byte-identical output; reorders I/O. PIPE=1 opts in.
PIPE_WORKERS	8	Number of pthread loaders when PIPE=1, or the io-wq worker maximum per ring when URING=1 (capped at 64). Tune to SSD queue depth and available cores.
URING	0 (off)	Linux-only queued expert I/O. URING=1 implies PIPE=1, forces cold reads through io-wq (IOSQE_ASYNC), replaces blocking loader pthreads and spin waits with batched SQEs/CQEs, and batches PILOT_REAL loads on a separate ring. Use DIRECT=1 for cold NVMe to avoid page-cache copy/readahead limits. Fails clearly if the kernel denies io_uring; incompatible with COLI_MMAP=1.
DIRECT	0 (off)	Use O_DIRECT/unbuffered reads for expert slabs. Helps sustained NVMe; keeps the zero-copy GPU path.
COLI_NO_OMP_TUNE	off	Kill-switch for the OpenMP hot-thread tuning (OMP_WAIT_POLICY=active spin + proc-bind). Set =1 when the CPU is mostly waiting on the GPU (Metal) so spin doesn't steal the shared power budget.
MLOCK	-1 (auto: on for macOS)	Wire the streamed expert cache into physical RAM (mlock) to dodge the memory compressor. 0 off, 1 force.
CAP_RAISE	1 (on)	Let the engine raise the expert-cache cap above topk when RAM allows (bigger batches). 0 fixes the cap.
PREFETCH	0	Prefetch depth for streamed experts.
COLI_MMAP	0	mmap the weights instead of read()-ing into slabs.
PIN	unset	Path to a .coli_usage/stats file; pins the hottest experts into a resident "hot store" at startup. PIN=auto seeds from the model dir's live .coli_usage (appended after every turn, so each restart's pin placement follows the accumulated real workload) with stats.txt as the fallback for a virgin model dir; neither present → no pin this run.
PIN_GB	10.0	Size budget (GB) for the pinned hot store when PIN is set.
AUTOPIN	1 (on)	Auto-pin the hot store from usage history once ≥5000 selections are recorded.
REPIN	0 (off)	Live re-pin the hot store every N emitted tokens (RFC).
PILOT	0 (off)	Router-piloted cross-layer expert prefetch.
PILOT_REAL	0 (off)	Value-preserving real cross-layer prefetch loads (PILOT_REAL=1 opts in).
PILOT_K	6 if PILOT_REAL else 8	Number of experts the pilot prefetches per step.
CACHE_ROUTE	0 (off)	Opt-in max-rank cache-aware MoE routing (pin∪LRU prefer within top-M). See CACHE_ROUTE.md.
ROUTE_J	2	Sacred top ranks always taken when CACHE_ROUTE=1.
ROUTE_M	12	Max-rank window for resident preference when CACHE_ROUTE=1.
ROUTE_P	0	Cumulative mass window for CACHE_ROUTE (0 = fixed M).
ROUTE_ALPHA	1	Scale gate mass of substituted experts before renorm (1 = off).
ROUTE_AGREE	auto	Overlap% + KL vs true top-K; auto-on when CACHE_ROUTE=1.
ABSORB	-1 (auto: absorbed for S≤4)	MLA attention absorption mode.
IDOT	1	Integer dot-product kernel. IDOT=0 uses exact f32 kernels (for A/B numerical checks).
COLI_POLICY	quality	Resource policy: quality, balanced, or experimental-fast.

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CUDA (NVIDIA)

Variable	Default	Effect
COLI_CUDA	off	Enable the CUDA backend. Requires a CUDA build.
COLI_GPU / COLI_GPUS	unset	Device selection (auto, none, or a list like 0,1). Requires COLI_CUDA=1.
CUDA_DENSE	0	Place dense (non-expert) matmuls on the GPU.
CUDA_EXPERT_GB	0	VRAM budget (GB) for caching experts on the GPU.
CUDA_RELEASE_HOST	auto (1 if >1 device)	Release host-side copies after upload.
COLI_CUDA_ATTN	off	Run S≤4 attention on the GPU.
COLI_CUDA_PROFILE	off	Emit CUDA timing.

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Advanced / experimental / debug

These are for testing, benchmarking, or internal use — not part of the everyday surface, and some may change without notice.

Variable	Default	Effect
SPEC	1	Speculative decoding on/off.
DRAFT	-1 (auto: 3 with MTP, else 0)	Number of speculative draft tokens per step.
GRAMMAR	unset	Path to a GBNF grammar file to constrain generation.
GRAMMAR_DRAFT	unset	Max grammar-forced draft span length.
DSA	on	Dynamic Sparse Attention indexer. DSA=0 disables.
DSA_FORCE	0	Force the DSA path on.
DSA_TOPK	model value	Override the DSA index top-k (testing).
LOOKA	0	Measure router predictability (instrumentation).
I4_ACC512 / I4_ACC512_TEST	off	int4 512-wide accumulator kernel toggle / self-test.
NOPACK	off	Disable weight packing.
DROP	off	Drop-related debug toggle.
PIN_FILL	0	Fill the pinned store even without usage data.
MTP_DEBUG / MTP_PRENORM / MTP_SWAP	off	MTP head debugging / ablations.
STATS	unset	Write an expert-usage histogram to STATS=<file> at end of run.
SCORE	unset	Scoring/eval mode over SCORE=<file>.
REF / REF_FORCE	ref_glm.json	Reference-output comparison mode.
REPLAY	unset	Replay mode.
TF	unset	Teacher-forcing mode.
CHAT_TEMPLATE	1	Apply the GLM chat template (0 = raw prompt).

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Server / CLI (openai_server.py, coli)

These are read by the Python programs (not the glm engine), so they don't appear in glm.c. They cover the OpenAI-compatible server, tool calling, and the debug view.

Variable	Default	Effect
COLI_DEBUG	0 (off)	Tee the engine transaction to stderr, by level. 1 = decoded model output stream only (byte-by-byte, on both the tool-call and plain paths). 2 = both sides — the fully-rendered prompt the engine received and the output, bracketed and correlated by request id, so stderr reads as the whole conversation. Invaluable for seeing what the model received vs. emitted during an OpenCode session.
COLI_TOOL_SALVAGE	0 (off)	Opt-in de-mangler: reconstruct a malformed int4 tool call by mapping its lone payload onto the tool's primary parameter. Never rewrites well-formed output; recommended for int4 deployments.
COLI_THINK	0 (off)	Make thinking the default when the client sends neither reasoning_effort nor enable_thinking. Any explicit client value still wins.
COLI_MODEL	unset	Default model directory (fallback for --model).
COLI_MODEL_ID	glm-5.2-colibri	Model id reported by the API.
COLI_API_KEY	unset	Required bearer token for the server.
COLI_MAX_QUEUE	8	Max queued requests.
COLI_QUEUE_TIMEOUT	300	Seconds a request may wait in the queue.
COLI_KV_SLOTS	1	Independent KV conversation slots (→ engine KV_SLOTS).
COLI_POLICY	quality	Resource policy (shared with the engine): quality | balanced | experimental-fast.
COLI_COLOR	auto (TTY)	COLI_COLOR=1 forces colored coli output when not a TTY.
COLI_RAW	0	coli raw output mode.

Debugging an OpenCode session: COLI_DEBUG=1 watches the model's output stream; COLI_DEBUG=2 shows both sides (prompt + output) as a transcript. Add COLI_TOOL_SALVAGE=1 on int4 to catch mangled tool calls.

Set by the CLI (don't usually set by hand)

coli / openai_server.py set these internally to select a run mode or pass through a flag:

• SNAP — model snapshot directory (required by glm; set from --model).
• SERVE, SERVE_BATCH — select serve / batched-serve mode.
• PROMPT — one-shot text mode.
• COLI_OMP_TUNED — internal sentinel guarding the OMP re-exec (see COLI_NO_OMP_TUNE); not user-facing.

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Worked example — the fast, reproducible Apple-Silicon config

# fast (sampling, non-deterministic by design):
COLI_METAL=1 DIRECT=1 COLI_NO_OMP_TUNE=1 PIPE=1 PIPE_WORKERS=6 MTP=0 \
  ./coli run --model /path/to/model --ram 113 "your prompt"

# same, but reproducible (greedy):
TEMP=0 COLI_METAL=1 DIRECT=1 COLI_NO_OMP_TUNE=1 PIPE=1 PIPE_WORKERS=6 MTP=0 \
  ./coli run --model /path/to/model --ram 113 "your prompt"