List all available credential names that can be used with browser_type_credential. Returns names and their source (env var or file), but NEVER the actual values. Credentials are stored locally and resolved by the MCP server.
AI agents call browser_list_credentials to retrieve information from MCProxy without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is a read-only operation that retrieves credential metadata without side effects. While listing credential names could inform an attacker about what credentials exist, the tool explicitly does not expose actual values, limiting its risk. The capability is informational and reversible, making it a Read category tool with low severity.
From the tool's definition Tool description states it 'List all available credential names' and 'NEVER the actual values'. It returns metadata (names and source) without exposing secrets.
Attacks that exploit this kind of access
List all available credential names that can be used with browser_type_credential. Returns names and their source (env var or file), but NEVER the actual values. Credentials are stored locally and resolved by the MCP server. It is categorised as a Read tool in the MCProxy MCP Server, which means it retrieves data without modifying state.
Register the MCProxy MCP server in PolicyLayer and add a rule for browser_list_credentials: 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 MCProxy. Nothing to install.
browser_list_credentials 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 browser_list_credentials 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 browser_list_credentials. 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.
browser_list_credentials is provided by the MCProxy MCP server (saladtechnologies/mcproxy). 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 →