TGMS — Agent-Native Bi-Temporal Graph Management System

A temporal graph database whose query surface is built for LLM agents — and whose answers can be audited claim by claim.

Project page & blog: https://zxf-work.github.io/tgms/ · Paper: paper/main.pdf

LLM agents are unreliable at exactly the things temporal graph analytics requires: arithmetic, identifiers, and asserting only what the evidence shows. TGMS's answer is architectural — give the model no opportunity to do any of them:

• a bi-temporal property graph (valid time × transaction time) that distinguishes evolution ("the edge ended") from correction ("we were wrong"), so agents can answer "what did we believe on March 1?" — a question latest-state snapshots and the RAG configurations we evaluated cannot express. Bi-temporality itself is inherited, not invented here — it has a four-decade literature, a place in SQL:2011, and production databases built around it. We measure against the clearest of those, XTDB: fed the same operation stream, the two systems agree on believed state at 400 of 400 probe points, with TGMS 3.9–4.7× faster at correction-heavy ingest on 23–27× less disk (the head-to-head);
• 15 verified temporal operators (reachability over time-respecting paths, δ-motifs, snapshot diffs, burst detection, interval joins, grouped aggregation over edge events, and the belief log itself) — typed, deterministic, bounded, cost-guarded, exposed as tools (MCP or in-process); identifiers must come from a resolver, arithmetic from a compute operator;
• a Planner–Executor–Verifier loop: the LLM only plans and reports; plans are statically validated (including a grounding rule that makes fabricated identifiers impossible and output-field contracts that reject invented result paths), executed deterministically with content-addressed traces, and every claim in the written answer is machine-checked against the trace that produced it — including truncation taint, so "correct arithmetic over incomplete evidence" is caught too;
• a purpose-built native storage engine (Rust, PyO3): bi-temporal columnar segments, a temporal-CSR traversal index, group commit, and a single-writer / many-reader concurrency mode — 24.6 bytes per edge version, versus 78.4 on ClickHouse and 549.7 on PostgreSQL for the same 1M-event log.

Does it work?

Three different questions, three different answers. All three are reported because the third is the least flattering.

1. Does the agent layer beat the alternatives? Dev-split campaign (CollegeMsg, open-source models served locally on one 24 GB GPU. "Answer accuracy" is normalized typed-answer accuracy — counts and values scored strictly, interval answers credited at IoU ≥ 0.5. Full receipts ship with the paper and the eval records in benchmarks/results-v1/):

• vs static-graph RAG: +36 points, paired-bootstrap 95% CI [0.18, 0.59]
• verifier fault injection: 500/500 injected false claims caught, 0 false positives; on the frozen campaign, 0 of 199 emitted answers contained an unsupported claim with gating (21 of 220 without it) — coverage is 199/282, so some of that is bought by declining to answer
• accuracy tracks planner capability where baselines stay flat: 13.8% / 34.0% / 62.8% at Qwen2.5 7B / 14B / 32B fp16, correction probes saturating at 100% at 32B

2. Is the engine competitive? Six systems answer one 13-query registry — TGMS native, TGMS-on-DuckDB, PostgreSQL, ClickHouse, Neo4j, Memgraph — with every cell hash-verified before it was timed:

The last row is the one we cannot close: ClickHouse keeps a factor of 2.2 on whole-window aggregation at both 1M and 10M, and it is a constant of the shape rather than something that grows with scale. Three rounds of profiling took that gap from 12× to 2.2× and each round found our own implementation rather than the workload. Single latency cells reproduce to about ±20% between days, which is stated everywhere they are quoted.

At 10M events the full query suite runs inside 1.76 GB of peak RSS, 16 concurrent readers get 10.2× the throughput of one, and a live writer costs those readers 0–3% of per-query latency.

3. Can it answer the questions people actually ask? This is the honest one. 110 questions were written by people who saw a plain-language description of two public datasets and never saw the operator list. Of those, 83 are expressible today — 10 were expressible when the study was pre-registered. Of LDBC SNB's 41 read templates, 3, and that number has not moved in eight sessions because 35 of the 38 misses need labelled multi-way pattern matching, which is a deliberately deferred design decision rather than a missing operator.

The store is good and the surface is narrow. Both instruments live in the repo (scripts/independent_questions.py, scripts/ldbc_fit.py), they re-run in seconds, and each capability shipped since has been scored against a forecast made before it was built — delivered/predicted has run 14/30, 4/7, 10/13, 14/16, 15/15, 4/8, 5/5 and 4/5. The last two were the first forecasts made per question rather than in aggregate, and they were right in every cell.

What the operators can express

Fifteen operators — fourteen of them unchanged since D-044, because the interesting growth since v0.4.0 happened inside them, driven question by question by the study above:

Every one of these is verified against the same brute-force oracle as the operators themselves, and every one is measured in the session that shipped it. What is not there is written down too, question by question, in the re-audit tables of scripts/independent_questions.py and scripts/ldbc_fit.py — both of which print the current blocked-capability board on report.

Quickstart

# macOS note: if this repo sits in an iCloud-synced folder, keep the venv
# outside it (iCloud sets the hidden flag on .pth files and Python 3.12+
# silently skips them):  export UV_PROJECT_ENVIRONMENT=$HOME/.venvs/tgms
uv sync --extra agent
make test                     # 271 tests: property, oracle, metamorphic, e2e

# build a real store + task suite (downloads CollegeMsg from SNAP)
make data-collegemsg suite-collegemsg

# call one verified operator — no LLM needed
uv run tgms call temporal_reachability \
  '{"src": "n9", "window": {"t_a": 1082040961000000, "t_b": 1088000000000000}}' \
  --store stores/collegemsg

# verifier acceptance experiment (deterministic, no LLM)
uv run tgms eval c2 --store stores/collegemsg \
  --suite stores/suite-collegemsg/suite.json --mutants 500

With any OpenAI-compatible LLM endpoint (e.g. vllm serve Qwen/Qwen2.5-7B-Instruct):

uv run tgms ask "How many nodes can n9 reach between ... and ...?" \
  --store stores/collegemsg --model openai/Qwen/Qwen2.5-7B-Instruct \
  --api-base http://localhost:8000/v1 --html trace.html   # auditable trace page

bash scripts/run_webapp.sh    # interactive guided demo at localhost:8080

Interfaces

Correctness

Every operator is verified against an independent brute-force oracle (500 randomized cases per operator; 97% line coverage in tgms/temporal/ across both backends), plus metamorphic properties — diff composition and bi-temporal immutability: any result pinned to a past belief state is byte-identical before and after later corrections. The same suite runs unmodified against both backends, which is the whole acceptance argument for the native engine: it has to satisfy the same human-owned ground truth that DuckDB does.

TGMS_TEST_BACKEND=native make test    # same tests, native engine

The write path is property-tested over random assert/retract/correct interleavings, and the append-only event log replays into either backend with identical store digests. Process rules are enforced in CI and are not advisory: tests and the oracle may never share a commit with the implementation they judge, and every number quoted on the project site is resolved from docs/site_facts.json at build time, so a stale figure fails the build rather than the review. See CONTRIBUTING.md.

Layout

tgms/core       clock, bi-temporal data model, error taxonomy
tgms/storage    StorageAdapter ABC, native + DuckDB backends, event log, TCSR index
tgms/temporal   operator algebra O1–O15 + brute-force oracle
tgms/tools      tool schemas, MCP server / ToolRouter, trace viewer, demo GUI
tgms/agent      plan IR, planner, executor, verifier, reporter, memory
tgms/data       dataset loaders (SHA-256 pinned) + synthetic generator
tgms/eval       task suites, baselines, matrix harness, metrics, fault injection
crates/         the native engine: bi-temporal segments, TCSR, motif kernel

Datasets are never bundled: loaders download from source (SNAP) and pin SHA-256 manifests. See docs/eval/ for design, positioning, measurements, and roadmap.

License

Apache-2.0 — see LICENSE. Cite via CITATION.cff.