Vaara — Claude Code MCP server: what it does, how to install
An accountability proxy for autonomous agents. It scores action risks, blocks unauthorized calls, and stores tamper-evident cryptographic receipts.
claude mcp add vaara -- uvx vaaraWhat Vaara does
Vaara intercepts tool execution before any payload runs. The proxy evaluates risk scores against active security policies. High-risk invocations raise immediate blocks until an operator approves them.
Decisions, parameters, and execution results append to a local hash chain at ~/.vaara/trail/audit.db. Each entry gets signed with Ed25519 using DSSE envelopes canonicalized by rfc8785 and cbor2. Anyone can inspect the exported ledger offline to confirm that logs were never modified.
The package requires Python 3.10+. Without historical run feedback, risk evaluation intervals stay wide, so critical calls escalate to humans early.
What it helps with
- Intercept risky tool invocations before execution starts
- Create tamper-evident action receipts using Ed25519 signatures
- Supply verifiable proof of autonomous behavior for external audits
- Halt executions that exceed risk score boundaries
Example prompts for the agent
- Intercept the tool call through Vaara before updating production data
- Export the signed cryptographic audit trail via
vaara trail export - Evaluate agent actions in shadow mode to observe risk scoring
How to install Vaara
Platform CLI
claude mcp add vaara -- uvx vaarauvx runs the command named after the package; if the README names another one, use uvx --from vaara <command>
Platform CLI
codex mcp add vaara -- uvx vaarauvx runs the command named after the package; if the README names another one, use uvx --from vaara <command>
Config file
{
"mcpServers": {
"vaara": {
"command": "uvx",
"args": [
"vaara"
]
}
}
}uvx runs the command named after the package; if the README names another one, use uvx --from vaara <command>
Config file
{
"servers": {
"vaara": {
"type": "stdio",
"command": "uvx",
"args": [
"vaara"
]
}
}
}uvx runs the command named after the package; if the README names another one, use uvx --from vaara <command>
Platform CLI
gemini mcp add vaara uvx vaarauvx runs the command named after the package; if the README names another one, use uvx --from vaara <command>
Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about Vaara
How to install Vaara in Claude Code?
Run claude mcp add vaara -- uvx vaara in your terminal. Ensure Python 3.10+ is available locally.
What does the Vaara MCP server do?
It acts as a governance gateway for agent operations. Vaara scores action risks, halts unapproved steps, and records verifiable cryptographic proof.
Where are audit trails stored?
Records write directly to ~/.vaara/trail/audit.db. History survives system reboots without publishing any data unless explicitly requested.
