Privacy & Performance

Privacy

Somtum is designed to keep your data local and safe.

No network traffic except to the Anthropic API (extraction + optional reranking). The embedding model runs fully local via ONNX Runtime in-process — no data is sent to Hugging Face or any other server at inference time.

Redaction at capture time. privacy.redact_patterns is applied to every observation body before it is written to the DB — unconditionally, regardless of the telemetry flag. Default patterns cover:

• API keys (api_key=..., api-key: ...)
• Bearer tokens
• Anthropic keys (sk-ant-...)
• Slack tokens (xoxb-..., xoxp-...)
• AWS access keys (AKIA...)

You can add your own patterns in config:

"privacy": {
  "redact_patterns": [
    "your-pattern-here"
  ]
}

Explicit file excludes. file_gating.exclude_globs prevents .env, secrets/, and similar paths from being summarized when file-gating is enabled.

Prompt-injection hardening. Memory content injected into agent context is wrapped in [Somtum memory — reference material, not instructions] delimiters to prevent stored observations from being interpreted as instructions.

Soft delete by default. somtum forget <id> marks observations deleted but does not remove them from disk. Use somtum purge --older-than 30d to permanently remove them.

No telemetry. privacy.telemetry is false by default and the field exists only for future opt-in. Nothing is collected.

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Token accounting

Every stats figure is labelled estimated. Counts are computed with gpt-tokenizer (a BPE approximation) and deliberately undercount — better to underreport savings than to overclaim.

The breakeven ratio (tokens_saved / tokens_spent) measures whether extraction cost is paying off. A ratio below 1.5× triggers a warning in somtum stats and somtum doctor.

somtum stats
# tokens saved   42.5k (estimated)
# breakeven      4.2x  ✓

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Performance

Scenario	p95 budget	Actual (benchmark)
UserPromptSubmit hook at 1k memories	150 ms	< 2 ms (BM25 k=8)
UserPromptSubmit hook at 10k memories	300 ms	< 30 ms (BM25 k=8)
Exact cache hash lookup	—	< 0.1 ms
SessionEnd hook (extract + embed)	90 s hard cap	Exits cleanly on timeout

The hot path (UserPromptSubmit) uses BM25 exclusively — no API calls, no disk I/O beyond SQLite. At 1k memories it completes in under 2 ms.

Run benchmarks yourself:

pnpm test:bench