CCAR-F Claude Code Configuration and Workflows Practice Question
Exhibit
[2023-11-01 10:15:42] DEBUG: Attempting to call tool: edit_file [2023-11-01 10:15:43] ERROR: Tool 'edit_file' failed. Reason: The provided 'old_string' was not found in the file 'src/auth.ts'. [2023-11-01 10:15:43] INFO: Suggesting retry to model...
Refer to the exhibit. A developer sees this error log in the terminal output. What is the most likely cause of this failure in the Claude Code workflow?
⚠ Common exam trap
Developers often assume the model has real-time file system awareness, forgetting that failed edits usually stem from stale context or desynchronized file states.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The model's context for 'src/auth.ts' is outdated or incorrect.
The 'edit_file' tool works by performing a search-and-replace operation. If the model's internal representation of the file is out of sync with the actual contents on disk, the operation will fail. This often happens if the file was modified by an external process or if the model's previous 'read' was incomplete.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The developer does not have write permissions for the file 'src/auth.ts'.
Why it's wrong here
Permissions errors would typically result in an 'EACCES' or 'Permission Denied' message from the operating system. The error in the exhibit specifically points to a content mismatch rather than a filesystem restriction, indicating that the tool was able to access the file but failed to find the target string.
- ✗
The model is attempting to edit a file that has been excluded by .claudeignore.
Why it's wrong here
If a file is ignored by .claudeignore, the model would generally not be able to see it or attempt to edit it in the first place. Errors regarding ignored files would occur during the initial discovery phase, not during a tool call that requires specific knowledge of the file's internal text content.
- ✓
The model's context for 'src/auth.ts' is outdated or incorrect.
Why this is correct
The error 'old_string not found' occurs when the model tries to replace a block of code that doesn't exactly match what is on the disk. This happens if the file changed since Claude last read it. The correct workflow is for the model to re-read the file to synchronize its state.
- ✗
The 'edit_file' tool has been disabled in the project's .claude.json configuration.
Why it's wrong here
If the tool were disabled, the CLI would prevent the model from even attempting the call, or it would return a 'tool not found' error. The exhibit shows the tool was successfully called but failed due to a logical mismatch in the string replacement parameters provided by the model.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Anthropic exam blueprint
This CCAR-F practice question is part of Courseiva's free Anthropic certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CCAR-F exam.