List available environment variable presets. These can be used when starting new sessions with happy_start_session.
AI agents call happy_list_environment_sets to retrieve information from Happy Server MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns a list of environment variable presets without creating, modifying, deleting, or executing anything. It has no side effects and poses minimal security risk as it only exposes metadata about available configurations.
From the tool's definition The tool description states it 'List[s] available environment variable presets' — a retrieval operation with no modification or execution capability. The verb 'list' is a classic Read operation.
Attacks that exploit this kind of access
List available environment variable presets. These can be used when starting new sessions with happy_start_session. It is categorised as a Read tool in the Happy Server MCP MCP Server, which means it retrieves data without modifying state.
Register the Happy Server MCP server in PolicyLayer and add a rule for happy_list_environment_sets: 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 Happy Server MCP. Nothing to install.
happy_list_environment_sets is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the happy_list_environment_sets 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 happy_list_environment_sets. 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.
happy_list_environment_sets is provided by the Happy Server MCP server (zhigang1992/happy-server-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
Teams ship this data inside their own products. See what a licence covers →