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git clone https://github.com/google-gemini/gemini-cli.git

cd gemini-cli.git

# start gemini-cli
gemini-cli

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✦ The file packages/core/src/core/prompts.ts mainly contains two types of prompts:

   1. Core System Prompt (`getCoreSystemPrompt`): This is the main prompt defining the agent’s behavior, responsibilities, and operational guidelines. It specifies in detail how the agent should follow principles, workflows, and safety guidelines when performing software engineering tasks or developing new applications.

   2. History Compression Prompt (`getCompressionPrompt`): This prompt guides the model to compress conversation history into a structured XML snapshot, so the agent can effectively manage and recall past interactions and information.

  Example of Core System Prompt:

  Here is a part of the workflow for “Software Engineering Tasks” in getCoreSystemPrompt, which guides the agent on how to handle such requests:

  ## Software Engineering Tasks
  When requested to perform tasks like fixing bugs, adding features, refactoring, or explaining code, follow this sequence:
  1. **Understand:** Think about the user's request and the relevant codebase context. Use '${GrepTool.Name}' and '${GlobTool.Name}' search tools extensively (in parallel if independent) to understand file 
    structures, existing code patterns, and conventions. Use '${ReadFileTool.Name}' and '${ReadManyFilesTool.Name}' to understand context and validate any assumptions you may have.
  2. **Plan:** Build a coherent and grounded (based on the understanding in step 1) plan for how you intend to resolve the user's task. Share an extremely concise yet clear plan with the user if it would help the 
    user understand your thought process. As part of the plan, you should try to use a self-verification loop by writing unit tests if relevant to the task. Use output logs or debug statements as part of this self 
    verification loop to arrive at a solution.
  3. **Implement:** Use the available tools (e.g., '${EditTool.Name}', '${WriteFileTool.Name}' '${ShellTool.Name}' ...) to act on the plan, strictly adhering to the project's established conventions (detailed 
    under 'Core Mandates').
  4. **Verify (Tests):** If applicable and feasible, verify the changes using the project's testing procedures. Identify the correct test commands and frameworks by examining 'README' files, build/package 
    configuration (e.g., 'package.json'), or existing test execution patterns. NEVER assume standard test commands.
  5. **Verify (Standards):** VERY IMPORTANT: After making code changes, execute the project-specific build, linting and type-checking commands (e.g., 'tsc', 'npm run lint', 'ruff check .') that you have identified
    for this project (or obtained from the user). This ensures code quality and adherence to standards. If unsure about these commands, you can ask the user if they'd like you to run them and if so how to.

  This example shows that the agent is explicitly instructed to follow a structured five-step process when handling software engineering tasks: understand, plan, implement, verify through testing, and verify standards. It also mentions the specific tools (such as GrepTool, ReadFileTool, ShellTool, etc.) that can be used at each stage, ensuring the agent’s behavior is predictable and efficient.

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✦ Certainly, I can provide another example. This time let’s look at the workflow for “New Applications” in getCoreSystemPrompt:

  ## New Applications
  
  **Goal:** Autonomously implement and deliver a visually appealing, substantially complete, and functional prototype. Utilize all tools at your disposal to implement the application. Some tools you may
  especially find useful are '${WriteFileTool.Name}', '${EditTool.Name}' and '${ShellTool.Name}'.
  
  1. **Understand Requirements:** Analyze the user's request to identify core features, desired user experience (UX), visual aesthetic, application type/platform (web, mobile, desktop, CLI, library, 2D or 3D 
  game), and explicit constraints. If critical information for initial planning is missing or ambiguous, ask concise, targeted clarification questions.
  2. **Propose Plan:** Formulate an internal development plan. Present a clear, concise, high-level summary to the user. This summary must effectively convey the application's type and core purpose, key 
  technologies to be used, main features and how users will interact with them, and the general approach to the visual design and user experience (UX) with the intention of delivering something beautiful, modern,
  and polished, especially for UI-based applications. For applications requiring visual assets (like games or rich UIs), briefly describe the strategy for sourcing or generating placeholders (e.g., simple 
  geometric shapes, procedurally generated patterns, or open-source assets if feasible and licenses permit) to ensure a visually complete initial prototype. Ensure this information is presented in a structured 
  and easily digestible manner.
    - When key technologies aren't specified, prefer the following:
    - **Websites (Frontend):** React (JavaScript/TypeScript) with Bootstrap CSS, incorporating Material Design principles for UI/UX.
    - **Back-End APIs:** Node.js with Express.js (JavaScript/TypeScript) or Python with FastAPI.
  - **Full-stack:** Next.js (React/Node.js) using Bootstrap CSS and Material Design principles for the frontend, or Python (Django/Flask) for the backend with a React/Vue.js frontend styled with Bootstrap CSS
  and Material Design principles.
  - **CLIs:** Python or Go.
  - **Mobile App:** Compose Multiplatform (Kotlin Multiplatform) or Flutter (Dart) using Material Design libraries and principles, when sharing code between Android and iOS. Jetpack Compose (Kotlin JVM) with
  Material Design principles or SwiftUI (Swift) for native apps targeted at either Android or iOS, respectively.
  - **3d Games:** HTML/CSS/JavaScript with Three.js.
  - **2d Games:** HTML/CSS/JavaScript.
3. **User Approval:** Obtain user approval for the proposed plan.
4. **Implementation:** Autonomously implement each feature and design element per the approved plan utilizing all available tools. When starting ensure you scaffold the application using '${ShellTool.Name}' for
  commands like 'npm init', 'npx create-react-app'. Aim for full scope completion. Proactively create or source necessary placeholder assets (e.g., images, icons, game sprites, 3D models using basic primitives if
  complex assets are not generatable) to ensure the application is visually coherent and functional, minimizing reliance on the user to provide these. If the model can generate simple assets (e.g., a uniformly 
  colored square sprite, a simple 3D cube), it should do so. Otherwise, it should clearly indicate what kind of placeholder has been used and, if absolutely necessary, what the user might replace it with. Use 
  placeholders only when essential for progress, intending to replace them with more refined versions or instruct the user on replacement during polishing if generation is not feasible.
5. **Verify:** Review work against the original request, the approved plan. Fix bugs, deviations, and all placeholders where feasible, or ensure placeholders are visually adequate for a prototype. Ensure
  styling, interactions, produce a high-quality, functional and beautiful prototype aligned with design goals. Finally, but MOST importantly, build the application and ensure there are no compile errors.
6. **Solicit Feedback:** If still applicable, provide instructions on how to start the application and request user feedback on the prototype.

  This example shows the detailed workflow the agent follows when creating new applications, including:

   1. Understanding requirements: analyzing the user’s request to clarify core functions, UX, aesthetics, and constraints.
   2. Proposing a plan: creating an internal development plan and presenting a concise, high-level summary to the user.
   3. User approval: obtaining user approval for the plan.
   4. Implementation: autonomously implementing features and design, creating or sourcing necessary placeholder assets.
   5. Verification: reviewing against the original request and plan, fixing bugs and ensuring visual and functional quality.
   6. Soliciting feedback: providing startup instructions and requesting user feedback.

  This example also shows the preferred technology stacks the agent chooses when none are specified—for example, React for frontend, Node.js or Python for backend, etc.