Selecting a custom function from available custom functions to be added into a playbook

A system comprising:

• one or more computers each including a processor and a memory, wherein the one or more computers are operable to execute instructions which cause the system to perform operations including:
• receiving a first input defining a custom function block;
• wherein the first input includes a specification of one or more input parameters to the custom function block, and user-provided executable source code defining functionality of the custom function block;
• adding the custom function block to a first playbook in response to user input;
• and
• executing, by a security operations application, the first playbook including the custom function block to perform security operations.

A non-volatile computer-readable media including instructions, which when executed by one or more computers each including a processor and a memory, cause the one or more computers to perform operations including:

• receiving a first input defining a custom function block;
• wherein the first input includes a specification of one or more input parameters to the custom function block, and user-provided executable source code defining functionality of the custom function block;
• adding the custom function block to a first playbook in response to user input;
• and
• executing, by a security operations application, the first playbook including the custom function block to perform security operations.