Implement Features With Claude Code Using Your Plan

Implement Features With Claude Code Using Your Plan

In this tutorial, you’ll learn how to leverage a detailed plan document created in a previous step to instruct Claude Code to implement new features in your project. We’ll cover selecting the appropriate Claude Code model, enabling advanced reasoning capabilities, and then instructing Claude to execute the plan, followed by a review of the generated code and final integration steps.

Prerequisites

• A completed plan document for the feature you wish to implement.
• Claude Code installed and configured.
• Basic understanding of your project’s codebase.

Step 1: Model Selection

While models like Sonic have been suitable for creating specifications and planning, implementing a feature often benefits from a more powerful model. For executing a plan, it’s recommended to switch to an Opus model, such as Opus 4.5, or the latest available leading Opus model. Opus models are generally better at adhering strictly to complex instructions outlined in a plan, minimizing deviations.

To switch models, use the model command within Claude Code and select the desired Opus model. For simpler features, sticking with Sonic might suffice, but for intricate or multi-step implementations, an Opus model is generally preferred.

Step 2: Configure Extended Thinking Mode

Extended thinking, also known as ‘thinking mode,’ allows Claude Code to spend more time reasoning about a task. This is particularly beneficial for complex, multi-step problems, as it gives the model extra capacity to explore solutions, self-correct, and identify potential issues within the plan. While this mode consumes more tokens due to the increased internal reasoning, it often leads to more robust implementations.

Enabling Extended Thinking:

1. Use the config command in Claude Code.
2. Locate the setting for ‘thinking mode’.
3. Toggle it on. This setting is usually saved globally for all your projects.

Tip: Thinking mode is often enabled by default. Unless you are making trivial changes, it’s generally advisable to keep it on.

Warning: Be mindful that using thinking mode, especially with Opus 4.5, can increase token consumption more rapidly. Monitor your token usage to avoid exceeding limits.

Quick Toggles:

• Mac: Press Option + T to quickly toggle thinking mode on or off.
• Windows: Press Alt + T to quickly toggle thinking mode on or off.

Single Prompt Activation: If thinking mode is off by default, you can trigger extended thinking for a single interaction by including the term ultrathing at the end of your prompt.

For this tutorial, we will keep thinking mode enabled and use the Opus 4.5 model.

Step 3: Instruct Claude Code to Implement the Plan

Ensure your plan document is open and accessible. Claude Code can often automatically use open documents as context.

1. Type the command: Can you implement this plan?
2. Press Enter.

Claude Code will now analyze the plan, reason about the implementation steps, and begin making the necessary code changes. It’s also recommended to enable autoedit mode at this stage, which allows Claude to directly modify files.

Step 4: Review Generated Code and Changes

Once Claude Code has finished implementing the plan (this may take a few minutes depending on the complexity), it’s crucial to review the changes. The AI might create new components, update existing files, and generate test files.

Review Process:

1. Examine the newly created components (e.g., button, input, login form, signup form, password input). Check their props, logic, and styling.
2. Verify updates to existing pages and files.
3. Inspect the generated test files to ensure they cover the new functionality and pass.
4. Look for any errors or warnings. The AI may automatically fix some issues, such as linting errors, and iterate on solutions.

Expert Note: While the AI can generate code quickly, dedicate sufficient time (potentially 30 minutes or more for complex features) to thoroughly understand every file created. This ensures you maintain full control and knowledge of your project’s direction.

For instance, the generated components might include:

• Button Component: With props for type (submit, reset, button), children, onClick, and disabled.
• Input Component: With props for label, onChange handler, and class names.
• LoginForm/SignupForm: Utilizing state for form inputs, submit handlers, and integrating the custom input and button components.
• PasswordInput Component: Featuring state management for password visibility and an icon to toggle between showing and hiding the password.

Step 5: Test the Implementation

After reviewing the code, preview the changes in a browser to ensure the new features function as expected.

1. Navigate to the relevant pages (e.g., login, signup).
2. Test all input fields and interactive elements, such as the password visibility toggle.
3. Verify that forms submit correctly and any console logs or actions are as anticipated.

Step 6: Commit and Integrate Changes

Once you are satisfied with the implementation and testing, commit the changes to your version control system.

1. Add the modified and new files to your staging area (e.g., using git add .).
2. Use a commit message command (e.g., git commit -m "Add authentication forms feature") to record the changes.

Local Branch Merging (Optional):

If you are working on a feature branch, you can merge these changes back into your main branch locally.

1. Ensure you are on the main branch (e.g., git switch main).
2. Merge your feature branch into the main branch (e.g., git merge ).

This completes a full cycle: from planning to implementation, review, testing, and integration. You can extend this workflow further by incorporating design references, code reviews, and other steps as needed.

Source: Spec Driven Workflow with Claude Code #4 – Implementing the Plan (YouTube)