// MCP TOOL REFERENCE

lerna

Runs Lerna monorepo commands (list, run, changed, version) and returns structured package information.

Accepts freeform code/query input (script); Accepts file system path (path)

Part of the Build MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.

// WHEN AI AGENTS USE THIS TOOL

AI agents invoke lerna to trigger processes or run actions in Build. Execute operations can have side effects beyond the immediate call -- triggering builds, sending notifications, or starting workflows. Rate limits and argument validation are essential to prevent runaway execution.

// WHY ENFORCE A POLICY ON LERNA

lerna can trigger processes with real-world consequences. An uncontrolled agent might start dozens of builds, send mass notifications, or kick off expensive compute jobs. Intercept enforces rate limits and validates arguments to keep execution within safe bounds.

// RECOMMENDED POLICY

Execute tools trigger processes. Rate-limit and validate arguments to prevent unintended side effects.

io-github-dave-london-build.yaml

tools:
  lerna:
    rules:
      - action: allow
        rate_limit:
          max: 10
          window: 60
        validate:
          required_args: true

See the full Build policy for all 9 tools.

// DETAILS

Tool Name lerna

Category Execute

MCP Server Build MCP Server

Risk Level High

// MORE BUILD TOOLS

Execute build Execute esbuild Execute nx Execute rollup Execute turbo Execute vite-build Execute webpack Write tsc

View all 9 tools →

// WHAT CAN GO WRONG

Agents calling execute-class tools like lerna have been implicated in these attack patterns. Read the full case and prevention policy for each:

Browse the full MCP Attack Database →

// OTHER EXECUTE TOOLS ACROSS MCP SERVERS

Other tools in the Execute risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.

Agent Passport System — Cryptographic Identity for AI Agents commerce_preflight Agent Passport System — Cryptographic Identity for AI Agents execute_with_context Agent Passport System — Cryptographic Identity for AI Agents gateway_execute_approval Agent Passport System — Cryptographic Identity for AI Agents governance_360 Agent Passport System — Cryptographic Identity for AI Agents parse_governance_block_html AgentClear — API Marketplace for AI Agents call_service

// IN CONTEXT OF HIGH RISK

lerna is one of the high-risk operations in Build. For the full severity-focused view — only the high-risk tools with their recommended policies — see the breakdown for this server, or browse all high-risk tools across every MCP server.

// RELATED READING

// FAQ

What does the lerna tool do? +

Runs Lerna monorepo commands (list, run, changed, version) and returns structured package information.. It is categorised as a Execute tool in the Build MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on lerna? +

Add a rule in your Intercept YAML policy under the tools section for lerna. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Build MCP server.

What risk level is lerna? +

lerna is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit lerna? +

Yes. Add a rate_limit block to the lerna rule in your Intercept policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block lerna completely? +

Set action: deny in the Intercept policy for lerna. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides lerna? +

lerna is provided by the Build MCP server (@paretools/build). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.

lerna

Enforce policies on Build