Install Mermaid

About Mermaid

Mermaid is an open-source, model-agnostic AI pair programmer for the terminal. It works with Ollama (local), Anthropic, Gemini, OpenAI, Groq, OpenRouter, and any OpenAI-compatible endpoint, with native tool calling, subagents, computer-use tools, and a clean TUI.

What's new in 0.18.0

Mermaid 0.18.0 Changed - BREAKING: Windows commands now run under PowerShell instead of cmd. Foreground and background execute_command on Windows spawn PowerShell (pwsh, falling back to Windows PowerShell 5.1) with -NoProfile -NonInteractive rather than cmd /C. Write commands in PowerShell syntax ($env:VAR, Get-ChildItem, Select-String); cmd-only syntax (%VAR%, if defined, & chaining) no longer works. Native exit codes now propagate — a failing cargo build surfaces its real code instead of collapsing to 0/1 — and background processes get a hidden console so they survive detached. The read-only-command allowlist and the destructive-command hard-deny both learned the PowerShell spellings (read-only cmdlets like Get-Content/Test-Path, and blocked shapes like Remove-Item -Recurse on dangerous roots). - BREAKING: write-capable MCP tools are vetted even in full_access. A new [safety] external_writes floor (allow | auto | ask | deny, default auto) means safety mode alone no longer authorizes an external side effect: an MCP tool without a server-advertised readOnlyHint is vetted against your request by the intent classifier — aligned calls run silently, off-task calls escalate to approval — in every mode, full_access included. Read-annotated tools are unaffected, and the hint is treated as untrusted (it never grants more than the mode already allows). Set external_writes = "allow" to restore the previous unconditional behavior. - BREAKING: machine-scoped package installs are vetted even in full_access. A new [safety] system_installs floor (same levels and auto default) gates system...

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