AI agents invoke compose-build to trigger actions in Cargo. 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.
Building Docker Compose service images is an Execute action—it triggers external build operations (Docker daemon commands) whose effects materially alter the system state (creates container images, consumes resources, modifies the build environment).
From the tool's definition Tool description states it 'Builds Docker Compose service images', which involves executing Docker build operations.
Attacks that exploit this kind of access
Builds Docker Compose service images and returns structured per-service build status. It is categorised as a Execute tool in the Cargo MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Cargo MCP server in PolicyLayer and add a rule for compose-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 Cargo. Nothing to install.
compose-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 compose-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 compose-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.
compose-build is provided by the Cargo MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.