compose-build
Builds Docker Compose service images and returns structured per-service build status.
This record as markdown: /tools/io-github-dave-london-docker/compose-build.md
What compose-build does on Docker
AI agents invoke compose-build to trigger actions in Docker. 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 compose-build is rated High
Building Docker images is an Execute-category action because it runs external build processes (docker-compose build) whose effects depend on the Dockerfile and build arguments provided. While builds are typically idempotent, they consume system resources, may pull external dependencies, and create artifacts whose behavior is difficult to predict without deep inspection.
From the tool's definition Tool name 'compose-build' and description 'Builds Docker Compose service images' indicates execution of Docker build operations that compile container images based on Dockerfiles and build context.
Attacks that exploit this kind of access
The rule that runs compose-build safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Docker, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For compose-build, this is the rule to start with:
compose-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 Docker, apply this rule, and every compose-build call is checked against it from then on.
Questions about compose-build
Builds Docker Compose service images and returns structured per-service build status. It is categorised as a Execute tool in the Docker MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Docker 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 Docker. 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 Docker MCP server (@paretools/docker). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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