harlequin

Harlequin is a terminal-based SQL IDE (TUI) implemented in Python. It provides an interactive interface to author, run, and browse/query data using pluggable database adapters (e.g., DuckDB default, SQLite, Postgres/MySQL via optional adapter packages).

Evaluated Mar 29, 2026 (0d ago)
Homepage ↗ Repo ↗ Ai Ml sql tui terminal-ide python database-adapters duckdb sqlite
⚙ Agent Friendliness
39
/ 100
Can an agent use this?
🔒 Security
31
/ 100
Is it safe for agents?
⚡ Reliability
30
/ 100
Does it work consistently?

Score Breakdown

⚙ Agent Friendliness

MCP Quality
0
Documentation
75
Error Messages
0
Auth Simplicity
95
Rate Limits
0

🔒 Security

TLS Enforcement
20
Auth Strength
20
Scope Granularity
10
Dep. Hygiene
65
Secret Handling
50

As a local tool, transport security depends on the database adapter/connection scheme (not documented in the provided content). The project relies on multiple third-party dependencies (textual/click/rich-click/etc.); no CVE status is provided here. Authentication/authorization is not a first-party concern; it is delegated to database drivers/connection strings, so correct secret handling and least-privilege are primarily user responsibilities.

⚡ Reliability

Uptime/SLA
0
Version Stability
50
Breaking Changes
40
Error Recovery
30
AF Security Reliability

Best When

You want an interactive SQL workflow directly in your terminal and can connect to a database using a supported adapter.

Avoid When

You need a dedicated HTTP/GraphQL/GRPC service interface or need managed SaaS features like user accounts, billing, and hosted environments.

Use Cases

  • Interactive SQL development in a terminal (editing, running, inspecting results)
  • Querying local or embedded databases (DuckDB/SQLite)
  • Adapting the IDE to various database engines via adapter plugins
  • Lightweight data exploration and export from a TUI workflow

Not For

  • A server-side API for remote clients (it’s a local CLI/TUI tool)
  • Managed database administration or secure multi-tenant environments
  • Use cases requiring webhooks, hosted dashboards, or cloud-managed services

Interface

REST API
No
GraphQL
No
gRPC
No
MCP Server
No
SDK
No
Webhooks
No

Authentication

Methods: None (local app)
OAuth: No Scopes: No

Harlequin is a local CLI/TUI. Authentication is determined by database connection strings/adapter requirements rather than a first-party service auth layer described here.

Pricing

Free tier: No
Requires CC: No

No pricing information is provided in the provided README/manifest content; it appears to be distributed as an open-source Python package (MIT) with optional adapter dependencies.

Agent Metadata

Pagination
none
Idempotent
False
Retry Guidance
Not documented

Known Gotchas

  • No MCP/REST contract for an agent to call; integration is primarily via invoking the CLI and interacting with a TUI.
  • Database operations are side-effecting (running queries); agent workflows should treat query execution as non-idempotent unless the user ensures it (e.g., read-only).
  • Adapter options/flags vary by installed adapter package; an agent may need to query available options via `harlequin --help` or consult adapter docs.

Alternatives

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Scores are editorial opinions as of 2026-03-29.

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