peek

Every screenshot in this README was produced by a single set_layout MCP call — see apps/desktop/scripts/screenshot.mjs.

peek is a desktop database GUI that doubles as an MCP server. Ask Claude to open a table, run a query, or arrange panels for comparison — it happens in the window in front of you, because AI tool calls and your own clicks share one command channel. A built-in chat panel runs Claude Code inside the app, so the agent you talk to drives the window it lives in.

Features

• 🤝 One UI for human and AI — every click and every MCP tool call is a Command on the same bus; no shadow state, no sync step

• 💬 Claude Code built in — the chat panel hosts it over ACP, wired back to peek's own MCP server

• 🛠️ 16 MCP tools — connect, introspect schemas, run queries, open views, control the layout, notify, ask the user

• 🔒 Read-only, enforced by the server — read-only transactions and flags, no keyword filtering anywhere

• 📎 Data reaches the AI only when you attach it — otherwise a query returns the model at most 20 rows

• 📦 Databases are plugins — six drivers load from ~/.peek/packages/<id>/; adding one means installing a directory

• ⚡ A million rows scroll — 0 dropped frames, ~0.5 s launch, 6.3 MB bundles (Performance)

• 🔑 Passwords live in the OS keychain — never plaintext on disk

Databases: PostgreSQL · MySQL · SQLite · Redis · Qdrant · Neo4j

Related MCP server: MCP Server for Database

Install

Download peek-v0.0.1-macos-arm64.zip from Releases, unzip, and drop peek.app into Applications. Apple Silicon only for now.

This build is ad-hoc signed (no Developer ID yet), so macOS will refuse the downloaded app as "damaged" on first launch. Clear the quarantine flag once and it opens normally:

xattr -d com.apple.quarantine /Applications/peek.app

Alternatively: System Settings → Privacy & Security → "Open Anyway". A signed and notarized build is planned.

Quick start

Requirements: Node ≥ 22, pnpm 10.32.1 (pinned via packageManager), and a database to point at. Developed and tested on macOS / Apple Silicon only so far.

pnpm install
pnpm dev              # opens the window; MCP server on port 7332
pnpm build            # production bundles into apps/desktop/out

In the app: pick a driver in the sidebar, paste a connection string, and browse. Connections that complete a handshake are saved automatically (passwords go to the OS keychain). Tables open as virtualized grids, SQL runs in a CodeMirror editor with ⌘⏎, panels split with ⌘\ / ⌘⇧\, and every result view has a cancel button backed by a real deadline.

Tests

pnpm -r typecheck     # strict TS across every package
pnpm -r test          # 2567 tests; driver suites need real servers (see below)

The desktop suite is pure logic and needs nothing. Each driver suite is an integration suite that reads its target from the environment and skips itself when the server is unreachable:

PEEK_TEST_PG_URL="postgresql://user@localhost:5432/your_db" \
PEEK_TEST_REDIS_URL="redis://localhost:6379" \
PEEK_TEST_QDRANT_URL="http://localhost:6333" \
PEEK_TEST_MYSQL_URL="mysql://root:pw@localhost:3306/peek_test" \
PEEK_TEST_NEO4J_URL="bolt://localhost:7687" PEEK_TEST_NEO4J_PASSWORD="…" \
pnpm -r test

Caveats: the Redis / Qdrant / MySQL / SQLite suites create and clean up their own fixtures; the PostgreSQL suite currently asserts against a specific development database (self-provisioning is a TODO); Neo4j always needs an explicit password. There is also an end-to-end smoke test of the built app (smoke-drivers.mjs) that drives every configured driver over MCP.

Using it from Claude Code

peek starts its MCP server on launch (loopback only, bearer-token authenticated) and writes the endpoint to ~/.peek/mcp.json (mode 0600). Register once:

claude mcp add peek --transport http http://127.0.0.1:7332/mcp \
  --header "Authorization: Bearer <token from ~/.peek/mcp.json>"

The exact command, token filled in, is one click away in Settings → MCP endpoint, which is also where you change the port or rotate the token.

The tools

There is deliberately no tool that hands a full result set to the model.

The chat panel

An ask call, suspended until the human answers — agents cannot answer their own questions.

You don't have to bring your own client: peek hosts Claude Code itself, as a tab. The embedded agent starts with no file tools, no shell, and no MCP servers other than peek's own — it does not inherit your settings.json, CLAUDE.md, or configured MCP servers, and verify-chat-security.mjs checks that against the real agent. Two settings (both off by default) let you opt back in: file/command tools, and MCP servers of your own. Each explains its cost next to the switch — see Security model.

Security model

• MCP server: loopback only, Authorization: Bearer required, Host/Origin checked against DNS rebinding, token compared in constant time and never logged.

• Read-only: enforced by the database server wherever one can (transactions, flags); Redis and Qdrant drivers simply issue no write command. One gap: a pre-existing stored procedure that opens its own read-write transaction — use a read-only database account for anything you care about.

• Process isolation: drivers run in one child process per connection; a wedged query or a crash cannot take the window down, and killing the process is an unconditional cancel. Package code never runs in the main process.

• Packages are trusted, not sandboxed. What you install is what you trust — the same deal as a VS Code extension or an MCP server. peek validates a package's manifest shape, isolates its processes, and strips credentials from their environment, but there is no signature check and no sandbox. Details in the design docs.

• Enabling the agent's file tools has a real cost: an agent that can read ~/.peek/mcp.json holds the bearer token, and permission prompts stop being a barrier. The settings panel says exactly this when the switch is on.

Performance

Measured on an Apple M2 Max (macOS, 120 Hz Retina) against a generated 1,000,000-row SQLite fixture, by two reproducible benchmark scripts (bench-startup.mjs, bench-scroll.mjs):

Results stream as columnar chunks with backpressure and an LRU cache, and the virtual scrolling is hand-written because Chromium silently clamps element heights around 699,000 rows at Retina resolution — no DOM dimension in peek is derived from the row count.

Status and limitations

Early but real: all six databases connect, introspect, and stream rows; the layout, chat, MCP surface, and package system described above are implemented and tested. pnpm build produces bundles, and package-mac.mjs produces a macOS .app; there is no signed installer yet. Writes are deliberately out of scope until the read-only path has fully stabilized.

Known limitations, briefly (details in docs/PLAN.md and docs/design/):

• A large query pauses (by design) at ~200k rows until you scroll further; rows evicted from the ~200 MB cache can't be re-fetched in place — re-run the query.

• Fixed 24 px row height; large values open in a modal.

• Accessibility is solid at the layout level (ARIA tablists, roving tabindex, focus management) but minimal inside panel bodies, and unverified against a real screen reader.

• A restored workspace reopens layout, tabs, and editor text, but never re-runs queries.

• Qdrant: no query cancellation (the API offers none — the button says so), and table headers can't sort yet.

• Stored credentials are as private as your OS user account; binary signing lands with the first published build.

Repository layout

peek/
├─ packages/
│  ├─ core/           # command schemas, workspace types, capability + chunk protocol, driver-host runtime
│  ├─ db-postgres/    # PostgreSQL driver
│  ├─ db-sql/         # MySQL + SQLite behind one dialect layer
│  ├─ db-redis/       # Redis driver
│  ├─ db-qdrant/      # Qdrant driver
│  └─ db-neo4j/       # Neo4j driver, plus the `graph` view kind
├─ apps/desktop/      # Electron app: main / preload / renderer, plus scripts/ (benchmarks, smoke tests)
└─ docs/              # PLAN.md (design record) and docs/design/ (per-change design docs)

docs/PLAN.md is the authoritative design record — architecture decisions, the performance budget, and milestone definitions (PLAN.zh-CN.md is the Chinese original). Per-change design docs live in docs/design/.

License

MIT. See LICENSE.