Point pgvis at your Postgres database. It introspects the schema, reloads it live on
NOTIFY pgrst, and serves it three ways from a single pipeline: typed Model Context Protocol tools for LLM agents, a
PostgREST-compatible REST API, and an OpenAPI 3.0 document. One parser, one planner, one
SQL builder — behavior stays consistent by design.
Every table and function becomes a typed Model Context Protocol tool — list_*, create_*, update_*, delete_*, call_* — with discovery resources like pgvis://schemas. No glue code. Works with Claude Desktop and any MCP client.
Same query DSL, the same Prefer header semantics, the same PGRST* error codes. A flat routing mode lets existing PostgREST clients keep working unchanged.
Generated from the same introspected schema as REST and MCP — always in sync by construction. Print it with pgvis openapi, or fetch it from the API root with Accept: application/openapi+json.
pgvis-core is I/O-free and depends on no driver. Backends implement a single Backend trait. Add a database API to any Rust app with the pgvis-lib Builder.
Parameterized SQL only. JWT verification (HS256/384/512, RS256, EdDSA) with exp, nbf and optional audience checks, role switching, and Row-Level Security. Secure defaults: binds to loopback, refuses to start without auth unless you pass --insecure-no-auth, and a token without a role is a 401.
BEGIN, role and claims, pre-request hook and query go out as one pipelined round trip. Table reads forward Postgres's JSON text without re-parsing. Optional in-memory response cache and health-checked, lag-aware read replicas; pool exhaustion returns 503.
The schema cache reloads on NOTIFY pgrst, 'reload schema' or SIGUSR1 — REST, OpenAPI and MCP pick up DDL without a restart. Opt-in pub/sub on Postgres LISTEN/NOTIFY: subscribe over SSE, publish over REST or MCP, with optional per-caller channel authorization by a SQL function.
Postgres (including PostgreSQL 18 virtual generated columns and temporal keys) and SQLite today. Dialect capability flags drive feature gating — no core rewrite needed for a new backend.
# build the CLI
cargo build --release --bin pgvis
# point it at your database (binds 127.0.0.1:3000)
export PGVIS_DSN="postgres://user@localhost/mydb"
# local dev only: no JWT, every request runs as the DSN's role.
# In production set PGVIS_JWT_SECRET and/or PGVIS_ANON_ROLE instead.
./target/release/pgvis serve --insecure-no-auth
# query
curl "http://localhost:3000/api/public/users?select=id,name&active=eq.true"// claude_desktop_config.json
{
"mcpServers": {
"pgvis": {
"command": "pgvis",
"args": [
"--dsn", "postgres://localhost/mydb",
"mcp"
],
"env": { "PGVIS_ANON_ROLE": "web_anon" }
}
}
}use pgvis_lib::Builder;
// REST + MCP-over-HTTP router for axum::serve
let router = Builder::new("postgres://localhost/mydb")
.schemas(vec!["public"])
.with_mcp_http()
.build()
.await?; pgvis-core does no I/O. Backends implement a single Backend trait
— Postgres and SQLite today — without touching the engine.
MCP is not a bolt-on. Tables and functions lower into typed MCP tools through the same plan → SQL path REST uses, so the two surfaces can never disagree.
The CLI is one consumer of pgvis-lib. Embed the same stack in any Rust
app with the Builder facade.
Routes default to /{prefix}/{schema}/{table} with a flat
PostgREST-compatible mode available via routing config for drop-in replacement.
Contributions welcome — issues, PRs, and design feedback all land on GitHub.