Test a regular expression against text.
AI agents call test_regex to retrieve information from MCP Server Fly without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool only performs pattern matching and evaluation on provided input strings. It reads and analyzes data but does not create, modify, delete, or execute any operations that would affect systems or data persistence. Testing regex patterns is a safe, informational operation commonly used for validation and analysis purposes.
From the tool's definition test_regex tool tests a regular expression against text without modifying, deleting, or executing external operations. The operation is purely analytical and returns results without side effects.
Attacks that exploit this kind of access
Test a regular expression against text. It is categorised as a Read tool in the MCP Server Fly MCP Server, which means it retrieves data without modifying state.
Register the MCP Server Fly MCP server in PolicyLayer and add a rule for test_regex: 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 MCP Server Fly. Nothing to install.
test_regex 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 test_regex 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 test_regex. 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.
test_regex is provided by the MCP Server Fly MCP server (kushalkachari993-dev/mcp-server-fly). 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.
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