variable-set
Sets a repository, organization, or environment GitHub Actions variable. Variables are not secret and may be visible in logs.
This record as markdown: /tools/io-github-dave-london-docker/variable-set.md
What variable-set does on Docker
AI agents use variable-set to create or update resources in Docker, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Docker environment.
Why variable-set is rated Medium
The tool performs a reversible modification (Write category) by setting GitHub Actions variables, which can be updated or deleted later. Severity is medium because while GitHub Actions variables are not secrets, modifying them could alter CI/CD behavior, potentially affecting build/deploy processes, though the blast radius is contained to GitHub Actions automation rather than direct code or infrastructure changes.
From the tool's definition Tool description states 'Sets a repository, organization, or environment GitHub Actions variable' — this creates or modifies configuration state in GitHub Actions that persists across workflows and executions.
Attacks that exploit this kind of access
The rule that runs variable-set 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 variable-set, this is the rule to start with:
variable-set stays usable, but capped: an agent stuck in a loop can't make hundreds of changes 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 variable-set call is checked against it from then on.
Questions about variable-set
Sets a repository, organization, or environment GitHub Actions variable. Variables are not secret and may be visible in logs. It is categorised as a Write tool in the Docker MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Docker MCP server in PolicyLayer and add a rule for variable-set: 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.
variable-set is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the variable-set 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 variable-set. 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.
variable-set 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.
More on Docker, and thousands of servers like it.
This server
Across the catalogue