The techniques and mechanisms described herein are directed to a taint mechanism. An object-based command declares a taint directive for a parameter within a command declaration. The taint directive is then associated with that parameter in a manner such that when an engine processes the command, the engine determines whether to process the command based on the taint directive and input for the parameter. The taint directive may specify that the input may be tainted or untainted. The command declaration may also include a taint parameter that specifies a taint characteristic for output from the command. The taint characteristic may be tainted, untainted, or propagated. Any type of object may become tainted. An untaint process may be applied to tainted data to obtain untainted data if an authorization check performed by the engine is successful.