Prompt Injector
Read & Rewrite Any Agent's System Prompt
Not affiliated with or endorsed by OpenAI, Google, or Apple.
Prompt Injector is a tool to customize AI agents and have them operate how YOU want them to. Apps often hardcode a hidden persona ("You are a helpful coding assistant…") and never show it to you. Prompt Injector lets you read that instruction and change it — including in clients that hide it completely, like Xcode.
Read what is actually there
Detect the system default prompts and instructions of a connected app, and read them for yourself. Rewrite it your way: Replace the system prompt entirely, or append, prepend, or partially replace it. Original GemPT functionality, still here: Force compatibility between providers for legacy client applications (Gemini and OpenAI, with Anthropic coming soon). Reliable: Works out of the box. No python scripts, no mess.
A note on technique
appending or prepending is recommended over replacing the prompt outright, because a full replacement erases the instructions the app relies on for tool use. Partial replacement is there for when you need to change one thing and leave the rest intact.
InspiratioNULL is not endorsed by Apple, OpenAI, or Google. InspiratioNULL does not own the following trademarks. "Xcode™", "macOS™", "iOS™", "watchOS™", "visionOS™", "tvOS™", and "iPadOS™" are trademarks of Apple, Inc. "ChatGPT™" is a trademark of OpenAI, "Gemini™" is a trademark of Google, LLC.
Every app, one click away
Free. The extras are optional.
Prompt Injector is free to use — no trial, no ads, no subscription. Some extras are available as an in-app purchase. If it saved you an afternoon, the tip jar is right there. If it annoyed you, the inbox is too.