Sqlsure MCP server

sqlsure

AI writes your SQL. sqlsure makes sure it's right.

A query can be perfectly valid, run without error, and return a number that's silently wrong — revenue double-counted by a join, an average summed, a patient identifier exposed. Databases don't catch this. Linters don't catch this. LLMs reviewing their own SQL don't catch this.

sqlsure does — deterministically, in 0.1 ms, before the query runs.

Proof, not promises: we ran sqlsure over the gold answers of the two

benchmarks every text-to-SQL model is graded on. **2,568 expert-written

queries, 45 flags, zero false alarms** — including a BIRD dev gold answer

that is provably wrong by 8× from the exact

bug class sqlsure targets, and a schema defect

now filed upstream.

How it works

sqlsure judges SQL against facts your team already declared — dbt unique tests become grain, relationships tests become join cardinality, one-line meta tags mark what's safe to sum. No new language to learn, no model to maintain by hand. Rules are dictionary lookups, not LLM calls: same input, same verdict, every time, offline.

Every rejection carries a machine-actionable fix, so AI agents self-repair: draft → check → fix → check → execute. In our benchmark, applying the fix verbatim produced a passing query 10/10 times.

Quick start

pip install sqlsure

from sqlsure import SemanticModel, check
violations = check(sql, model)   # [] means semantically safe

Or clone and run the 30-second demo:

python check.py                   # 5 wrong queries rejected, 1 approved — with fixes
python -m sqlsure.scan path/to/dbt-repo --report report.md   # audit any dbt repo

Three doors, one engine

1. CI gate — blocks the merge when a PR double-counts:

python -m sqlsure.cli --model model.json query.sql   # exit 1 on violations

2. MCP server — your AI agent must pass inspection before executing:

claude mcp add sqlsure -- python -m sqlsure.mcp_server --model /abs/path/model.json

See docs/MCP.md for tool reference and agent-loop patterns.

3. Library — embed check() inside any text-to-SQL product or agent framework. A drop-in SemanticGate wraps Vanna/WrenAI-style generators; a semantic eval metric scores NL2SQL output where execution-accuracy is blind.

Also available as an Agent Skill — a single SKILL.md your agent loads directly; no server process needed.

The rules (v0.1)

When sqlsure can't verify something, it says "can't verify" — never "looks fine." Honest uncertainty is a feature.

Trust properties

Shortened. The full README is on GitHub.