elstongun/leviathan

Deep memory for agents over large datasets.
Index any table, export or log once; your agent gets the few records that answer the question.

Leviathan is a single binary that turns records (JSONL, JSON, CSV/TSV, SQLite, or any database CLI's output) into a ranked full-text index. Agents ask in plain words and get short, cited result cards: ~450 tokens per answer at any dataset size, instead of grepping and reading raw history.

| At 1M records (678 MB) | Leviathan | best grep strategy | |---|---:|---:| | Median tokens per question | 436 | 107,122 (245×) | | Relevant record returned | 99.0% top 5 · 98.5% rank 1 | 96.0% within a 30K-char output | | Worst case (1,200 questions) | 602 tokens | 9.7M tokens | | Median latency | 33 ms | 92 ms |

Measured on a synthetic maintenance log (one example dataset; nothing in Leviathan is specific to it). Methodology, all six scales and caveats: docs/BENCHMARKS.md.

Quickstart

cargo install leviathan-index       # or: cargo install --git https://github.com/elstongun/leviathan
cd examples/tickets && leviathan index
leviathan search -g acme "sso login loop after password reset"

leviathan search · customer C-ACME "Acme Corp" (7 tickets) · query "sso login loop after password reset" · shown 3 of 3 · 24 tickets indexed
[1] T-1001 · 2024-01-08 09:12 · rel 16.9
  Login loops back to sign-in page after password reset
  status: closed · priority: high
  resolution: Cleared stale session cookies on password reset; shipped in 4.2.1. Workaround: clear site data.
  match: Users who reset their password get redirected to the sign-in page again in an endless loop.
...

• -g accepts a key, name or partial name. Ambiguous or unknown groups list candidates and exit 3, never guess.
• No match in the group falls back to other groups, labeled OTHER CUSTOMER.
• Combine --where field=value, --since/--until, "phrases" and -exclusions.

Prebuilt binaries are on Releases. No runtime dependencies; the index is one SQLite file.

Map your data

Fields are paths (a.b, items[].name); only id is required.

| Field | Enables | |---|---| | id | get, upsert, delete, citations | | title / text | Card headline (weighted 2×) / searched text (default: all strings) | | group / group_name | -g scoped search, name resolution, labeled fallback | | date | --since, --until, recent | | filters / display | --where facets / fields shown on cards | | empty_values / rank.boost | Placeholders treated as missing / favor complete records |

leviathan init ./export                       # infer a commented leviathan.toml
leviathan index tickets.csv --id "Ticket ID" --group customer_id --date created_at   # or flags
leviathan index -c tickets.toml               # or a config your agent wrote from the schema
leviathan describe                            # fields, groups, filter values, example calls

Any database works through its own CLI; Leviathan never holds credentials:

psql "$DATABASE_URL" -At -c "SELECT row_to_json(t) FROM tickets t" | leviathan index - -c tickets.toml
leviathan index app.db --sql "SELECT * FROM tickets" -c tickets.toml
duckdb -json -c "SELECT  FROM 'events/.parquet'" | leviathan index - -c events.toml

Builds are atomic and skipped when nothing changed; upsert and delete keep an index fresh. Full reference: docs/CONFIG.md.

Plug it into your agent

CLI + skill (recommended): any agent with a shell can call it. Copy skills/leviathan into ~/.claude/skills/ or paste it into AGENTS.md / .cursor/rules. Costs 0 tokens until used.

MCP (optional): leviathan mcp serves four read-only stdio tools (search, resolve_group, get, describe) whose descriptions include a summary of your dataset (~640 tokens per session). `leviathan wrap ` prints the config.

Commands

| Command | Does | |---|---| | init / index / upsert / delete | Propose a mapping / build / update / remove records | | search [-g G] [words] | Ranked records (--scope, --where, --since, --until, -n, --offset) | | recent [-g G] · resolve · get · describe | Newest · group candidates · full records · index summary | | mcp · wrap | MCP server · agent config |

Global: --index PATH, --json, --max-chars N. Exit codes: 0 ok (zero hits included), 1 error, 2 bad request, 3 group unknown/ambiguous.

How it works

Records stream into one SQLite file with an FTS5 index. A search resolves the group (exact → name → contains → fuzzy), runs one FTS5 match where group and filter values are indexed tokens (no post-filtering), ranks by BM25 × boosts, and decodes only the top N into capped cards. A record's own group name is excluded from scoped matching, placeholders count as missing, and every answer reports shown N of M so agents can tell "no match" from "no data".

Reproduce the benchmark

python3 -m venv bench/.venv && bench/.venv/bin/pip install -r bench/requirements.txt
bench/.venv/bin/python bench/run_bench.py && bench/.venv/bin/python bench/report.py   # ~30 min, ~4 GB

Contributing, security, license

See CONTRIBUTING.md (ranking changes need before/after benchmark numbers) and SECURITY.md (read-only, offline, unsafe-free; report privately). Licensed under Apache-2.0; dependencies in THIRD_PARTY.md.