| VAULT_PATH | Yes | Absolute path to your Obsidian vault (or any folder of .md files). |
| DATA_DIR | No | Where to store the SQLite index + embedding cache. Defaults to $XDG_DATA_HOME/obsidian-brain or ~/.local/share/obsidian-brain. |
| EMBEDDING_PRESET | No | Preset name: english (default, bge-small-en-v1.5), english-fast, english-quality, multilingual, multilingual-quality, multilingual-ollama. Ignored when EMBEDDING_MODEL is set. |
| EMBEDDING_MODEL | No | Power-user override: any transformers.js checkpoint or Ollama model id. Takes precedence over EMBEDDING_PRESET. Switching auto-reindexes. |
| EMBEDDING_PROVIDER | No | Embedding backend. 'transformers' (local, default) or 'ollama' (requires a running Ollama server). |
| OLLAMA_BASE_URL | No | Base URL of a local Ollama server. Only used when EMBEDDING_PROVIDER=ollama. |
| OLLAMA_EMBEDDING_DIM | No | Override the embedding dimensionality when EMBEDDING_PROVIDER=ollama. If unset, the server probes the model on startup. |
| OLLAMA_NUM_CTX | No | Override Ollama's num_ctx for embed requests. Leave UNSET to let obsidian-brain auto-detect via `/api/show`'s `context_length` (e.g. nomic-embed-text=2048, bge-m3=8192, qwen3-embedding:0.6b=32 768). Setting this manually imposes a hard cap and may silently truncate longer inputs — see https://github.com/ollama/ollama/issues/14259. Ollama's own default is 2048 which truncates for any model trained on a larger context. See also https://github.com/ollama/ollama/issues/7008. Fallback when both env is unset AND /api/show is unreachable: 8192. |
| OBSIDIAN_BRAIN_OLLAMA_AUTO_PULL | No | Auto-pull the configured Ollama model when /api/show returns 404 (model not present). Default ON — choosing an Ollama-backed preset is implicit consent to download its model. Streams /api/pull progress to stderr. Set to '0' to disable auto-pull entirely (master kill-switch) and fall back to the actionable error path (`HTTP 404 — try: ollama pull <model>`). |
| OBSIDIAN_BRAIN_OLLAMA_BYOM_AUTO_PULL | No | Opt-in to auto-pull for BYOM (custom EMBEDDING_MODEL) Ollama models OUTSIDE Ollama's official `library/` namespace. Default OFF — third-party models (e.g. `user/custom-fork`, `myregistry.com/team/model`) require this env var to be set to `1` before they will auto-pull, to prevent silent downloads of arbitrary user-named artifacts. Preset-known models (via EMBEDDING_PRESET) and bare model ids in the official library (e.g. `qwen3-embedding:0.6b`, `library/llama3:8b`) continue to auto-pull by default per the existing OBSIDIAN_BRAIN_OLLAMA_AUTO_PULL behavior. |
| OBSIDIAN_BRAIN_NO_WATCH | No | Set to '1' to disable the live chokidar file watcher. Useful on SMB/NFS vaults where FSEvents/inotify don't fire reliably — fall back to running `obsidian-brain index` on a schedule (launchd/systemd). |
| OBSIDIAN_BRAIN_NO_CATCHUP | No | Set to '1' to skip the startup catchup reindex pass that picks up edits made while the server was down. The live file watcher still starts (via OBSIDIAN_BRAIN_NO_WATCH=1 to disable that separately), and first-time indexing on an empty DB is unaffected — this knob only governs the post-restart `enqueueBackgroundReindex` walk. |
| OBSIDIAN_BRAIN_WATCH_DEBOUNCE_MS | No | Per-file reindex debounce for the live watcher, in milliseconds. |
| OBSIDIAN_BRAIN_COMMUNITY_DEBOUNCE_MS | No | Graph-wide community-detection (Louvain) debounce for the live watcher, in milliseconds. Louvain is the only expensive op — batching it prevents per-edit CPU spikes. |
| OBSIDIAN_BRAIN_TOOL_TIMEOUT_MS | No | Per-tool-call timeout in milliseconds. Tools exceeding this return an MCP error instead of hanging. |
| OBSIDIAN_BRAIN_MAX_CHUNK_TOKENS | No | Override the adaptive chunk-size budget (in tokens). When set, this beats the capacity probed from the model's tokenizer or Ollama /api/show. Use for debugging or for models with stale tokenizer configs. |
| OBSIDIAN_BRAIN_CONFIG_DIR | No | Override the per-user config directory where obsidian-brain stores model overrides (`model-overrides.json`) and the user-fetched seed (`seed-models.json`). Default is `$XDG_CONFIG_HOME/obsidian-brain` on macOS/Linux (or `~/.config/obsidian-brain`) and `%APPDATA%/obsidian-brain` on Windows. Both files survive `npm update obsidian-brain` because they live outside the package. |
| OBSIDIAN_BRAIN_DEBUG | No | Set to "1" to print a verbose synchronous startup trace to stderr — every preflight, createContext, server.connect, and shutdown step is logged with a monotonic timestamp. The LAST line before any silent failure tells you exactly which step the server reached. No-op when unset (no overhead). Use to diagnose silent-crash failure modes. |
| OBSIDIAN_BRAIN_LOG_FORMAT | No | Set to 'ndjson' for one-JSON-object-per-line stderr output (timestamp + level + message + structured fields). Default is human-readable plain text (`obsidian-brain: <message>`). Useful for piping logs into aggregators (Datadog, Loki, Vector, journald) that index structured fields. |