TOML configuration

mistralrs from-config -f <path> reads a TOML file. The top-level command field selects serve or run. Every key maps to a CLI flag of the same subcommand; the mapping is listed per table below. For per-flag semantics, see the generated CLI reference.

Minimal example

command = "serve"

[server]
host = "0.0.0.0"
port = 1234

[[models]]
model_id = "Qwen/Qwen3-4B"

[models.quantization]
quant = "4"

mistralrs from-config -f this.toml runs the server.

Top-level fields

Field	Type	Applies to	Purpose
command	string	both	"serve" or "run".
default_model_id	string	serve	Model id treated as the default. Must match one of the [[models]] entries.
thinking	bool	run	Force thinking mode on or off for models that support it (alias: enable_thinking). Omit to defer to the chat template default. Maps to --thinking on mistralrs run.

[global] section

Field	CLI flag	Default	Purpose
seed	--seed	not set	Sampling seed.
log	-l, --log	not set	Log file for requests/responses.
token_source	--token-source	cache	Token source string (literal:<token>, env:<var>, path:<file>, cache, none).

-v/--verbose has no TOML equivalent; use RUST_LOG instead.

[runtime] section

Field	CLI flag	Default	Purpose
max_seqs	--max-seqs	32	Max concurrent sequences.
no_kv_cache	--no-kv-cache	false	Disable KV cache entirely.
prefix_cache_n	--prefix-cache-n	16	Prefix caches retained (0 to disable).
chat_template	-c, --chat-template	not set	Custom chat template file (.json or .jinja), applied to every model. Per-model chat_template in [[models]] overrides it.
jinja_explicit	-j, --jinja-explicit	not set	Explicit Jinja template override. Per-model jinja_explicit also exists.
matformer_config_path	--matformer-config-path	not set	MatFormer (nested-submodel) slice config (CSV/JSON).
matformer_slice_name	--matformer-slice-name	not set	MatFormer slice to load. Requires matformer_config_path.
mtp_model	--mtp-model	not set	MTP (multi-token prediction) assistant model id or path.
mtp_n_predict	--mtp-n-predict	not set	MTP draft tokens proposed per target step.
mcp_config	--mcp-config	not set	MCP (Model Context Protocol) client configuration JSON for outbound servers. Also reads MCP_CONFIG_PATH if unset.
agent	--agent (alias --agentic)	false	Shortcut for enable_search = true + enable_code_execution = true + enable_shell = true.
enable_search	--enable-search	false	Enable the built-in web search tool.
search_embedding_model	--search-embedding-model	not set	Search reranker; embedding-gemma is the only accepted value. Requires enable_search (or agent).
enable_code_execution	--enable-code-execution	false	Enable Python code execution.
code_exec_python	--code-exec-python	python on Windows, python3 elsewhere	Python interpreter. Requires enable_code_execution (or agent).
code_exec_timeout	--code-exec-timeout	60	Per-call timeout in seconds. Requires enable_code_execution (or agent).
code_exec_workdir	--code-exec-workdir	per-session temp dir	Code execution working directory. Requires enable_code_execution (or agent).
enable_shell	--enable-shell	false	Enable the built-in shell tool for Responses tools[*].type="shell".
shell_path	--shell-path	/bin/sh on Unix, cmd on Windows	Shell executable. Requires enable_shell (or agent).
shell_timeout	--shell-timeout	600	Per-call shell timeout in seconds. Requires enable_shell (or agent).
shell_workdir	--shell-workdir	per-session temp dir	Root directory for per-session shell working directories. Requires enable_shell (or agent).
skills_dir	--skills-dir	system temp dir	Directory for uploaded OpenAI-compatible Skills. Requires enable_shell (or agent).
agent_permission	--agent-permission	auto	auto, ask, or deny: whether model-requested agent actions run automatically, require approval, or are denied. code_exec_permission / --code-exec-permission are accepted as aliases.

[server] section (serve only)

Field	CLI flag	Default	Purpose
host	--host	0.0.0.0	Bind address.
port	-p, --port	1234	TCP port.
no_ui	--no-ui	false	Disable the built-in web UI (mounted at /ui by default).
mcp_port	--mcp-port	not set	Also expose the loaded model as an MCP server on this port (JSON-RPC 2.0 at POST /mcp). See serve over MCP.
max_tool_rounds	--max-tool-rounds	not set	Default cap on agentic tool loop rounds. Per-request values from the HTTP API override it; the safety cap is 256 when unset.
tool_dispatch_url	--tool-dispatch-url	not set	URL to POST tool calls to for server-side execution. Only configurable server-side, never per-request.
disable_access_log	--disable-access-log	false	Disable info-level HTTP access logs.
access_log_format	--access-log-format	text	Access-log format: text or json.
access_log_health	--access-log-health	false	Include health, metrics, docs, and UI requests in HTTP access logs.
disable_request_id_header	--disable-request-id-header	false	Stop echoing x-request-id on responses.
disable_metrics	--disable-metrics	false	Disable Prometheus HTTP metrics and recorder installation.

Caution

The default host = "0.0.0.0" binds on all interfaces, exposing the server to your network. There is no built-in authentication. Set host = "127.0.0.1" for local-only access, or put an authenticating reverse proxy in front before exposing it.

The MCP client configuration (mcp_config) lives under [runtime], not [server]: it applies to run as well as serve.

[paged_attn] section

Field	CLI flag	Default	Purpose
mode	--paged-attn	auto	auto (on for CUDA, off for Metal/CPU), on, or off.
context_len	--pa-context-len	not set	Allocate KV cache for this context length.
memory_mb	--pa-memory-mb	not set	KV cache budget in MB. Conflicts with context_len.
memory_fraction	--pa-memory-fraction	not set	KV cache budget as fraction of VRAM (0.0 to 1.0). Conflicts with context_len and memory_mb.
block_size	--pa-block-size	not set	Tokens per block.
cache_type	--pa-cache-type	auto	KV cache quantization type.

[sandbox] section

OS-level isolation for the code-execution subprocess. Mechanics and threat model: sandbox reference.

Field	CLI flag	Default	Purpose
mode	--sandbox	auto	auto (on for Linux/macOS, no-op elsewhere), on (missing isolation is a hard error), or off.
profile	--sandbox-profile	profile-dependent	developer for agent/code/shell tools, otherwise restricted.
max_memory_mb	--sb-max-memory-mb	2048	Per-session memory cap in MiB.
max_cpu_secs	--sb-max-cpu-secs	600	Per-session CPU time cap in seconds. When rlimits apply, this is raised before execution to at least the enabled code or shell timeout.
max_procs	--sb-max-procs	64	Per-session process/thread cap.
network	--sandbox-network	profile-dependent	none, loopback, or full. Defaults to full for developer, loopback for restricted.

[[models]] array

Each entry defines one loaded model.

Field	Type	Required	Purpose
kind	enum	no	Defaults to auto. Set to text, multimodal, diffusion, speech, or embedding only to force a loader.
model_id	string	yes	Hugging Face id or local path.
tokenizer	path	no	Local tokenizer.json.
arch	enum	no	Architecture override (text models).
dtype	enum	no	auto, f16, bf16, f32.
chat_template	path	no	Chat template override for this model.
jinja_explicit	path	no	Jinja override for this model.
matformer_config_path	path	no	MatFormer slice config (CSV/JSON).
matformer_slice_name	string	no	MatFormer slice to load.

Each [[models]] entry can carry nested sections whose field shapes mirror the corresponding CLI flags:

Section	Purpose
[models.format]	Weight format selection (e.g. GGUF file/repo).
[models.adapter]	LoRA/X-LoRA adapter configuration.
[models.quantization]	Quantization: quant (front-door, same as --quant), isq (explicit ISQ, same as --isq), from_uqff, isq_organization, imatrix.
[models.device]	Device placement: cpu, device_layers, topology, hf_cache, max_seq_len, max_batch_size. cpu must be consistent across every entry.
[models.multimodal]	Multimodal load-time caps (image/video/audio limits).

Multi-model example

command = "serve"
default_model_id = "Qwen/Qwen3-4B"

[server]
host = "0.0.0.0"
port = 1234

[runtime]
enable_search = true
search_embedding_model = "embedding-gemma"

[[models]]
model_id = "Qwen/Qwen3-4B"

[models.quantization]
quant = "4"

[[models]]
model_id = "google/gemma-4-E4B-it"

[models.quantization]
quant = "4"

Validation

Invalid configs abort startup with a message identifying the problem:

• At least one entry in [[models]].
• default_model_id matches a model_id in [[models]].
• cpu is consistent across all models when set.
• search_embedding_model requires enable_search = true (or agent = true).
• code_exec_python, code_exec_timeout, and code_exec_workdir each require enable_code_execution = true (or agent = true).

CLI usage notes

Flag interactions that hold on the command line and as TOML keys:

• quant (CLI --quant, TOML key quant) is the front door: it tries a prebuilt UQFF (Universal Quantized File Format) first and falls back to ISQ (in-situ quantization). It conflicts with isq (--isq, the explicit ISQ level) and from_uqff (--from-uqff). mistralrs tune rejects quant = "auto" (--quant auto) because tune is the recommender.
• --calibration-file conflicts with --imatrix.
• --xlora conflicts with --lora. --xlora-order and --tgt-non-granular-index require --xlora; --xlora alone is accepted.
• --matformer-slice-name requires --matformer-config-path.
• mistralrs run: --image, --video, and --audio require -i/--input.
• mistralrs bench: --prompt-len and --depth accept comma-separated values for sweeps.
  • Each --prompt-len value produces a prefill measurement at that prompt length.
  • Each --depth value produces a decode measurement that prefills depth tokens and then generates --gen-len tokens.
  • --depth must be greater than 0 when --gen-len is greater than 0.

Server behavior notes

• CORS and body limit. Not exposed as CLI flags or TOML keys. Defaults: any origin; methods GET, POST, PUT, DELETE; allowed headers Content-Type, Authorization, x-api-key, anthropic-version, anthropic-beta, x-request-id; exposed headers x-request-id; 50 MB request body limit. Configure programmatically through MistralRsServerRouterBuilder in mistralrs-server-core.
• Authentication. mistral.rs does not implement authentication. Put a reverse proxy (nginx, Caddy, Traefik) in front for auth and TLS. OpenAI-protocol clients always send Authorization: Bearer ... because the OpenAI SDK requires an API key; mistral.rs does not validate the header.
• Logging and metrics. Access logs are written to normal server stdout/stderr by default, with request ids and route/status/latency metadata. GET /metrics exposes Prometheus HTTP metrics by default. See observability.
• Payload logging. -v enables debug detail and -vv trace-level file/cache internals; RUST_LOG module filters (e.g. RUST_LOG=mistralrs_core=debug,tower_http=info) override both. -l <path> logs all requests and responses to a file.