app_build
Build a .0n application bundle — a portable encrypted file containing endpoints, workflows, operations, automations, and connections. Deploy anywhere with: 0nmcp app run <file> Example: app_build({ name:
This record as markdown: /tools/io-github-0nork-0nmcp/app-build.md
What app_build does on 0nmcp
AI agents invoke app_build to trigger actions in 0nmcp. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
Why app_build is rated High
This tool runs a build process that compiles and bundles application components into a deployable artifact. It executes external tooling (0nmcp) and produces a portable encrypted file that can subsequently be run anywhere. The blast radius is high because a misused build could bundle malicious workflows, automations, or connections into a deployable package that could be executed on any system.
From the tool's definition 'Build a .0n application bundle' and 'Deploy anywhere with: 0nmcp app run <file>' — triggers a build/compilation process that packages endpoints, workflows, operations, automations, and connections into an executable bundle
Attacks that exploit this kind of access
The rule that runs app_build safely
PolicyLayer is an MCP gateway: it sits between your AI agents and 0nmcp, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For app_build, this is the rule to start with:
app_build stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect 0nmcp, apply this rule, and every app_build call is checked against it from then on.
Questions about app_build
Build a .0n application bundle — a portable encrypted file containing endpoints, workflows, operations, automations, and connections. Deploy anywhere with: 0nmcp app run <file> Example: app_build({ name:. It is categorised as a Execute tool in the 0nmcp MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the 0n MCP server in PolicyLayer and add a rule for app_build: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches 0nmcp. Nothing to install.
app_build is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the app_build rule in your PolicyLayer 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.
Set action: deny in the PolicyLayer policy for app_build. 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.
app_build is provided by the 0n MCP server (0nmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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