Claude Code does not reliably follow CLAUDE.md project instructions across sessions

Description

Claude Code does not reliably follow instructions specified in CLAUDE.md project instruction files, particularly when starting new sessions without prior conversation history.

Steps to Reproduce

1. Create a CLAUDE.md file in the project root with specific instructions (e.g., "When generating test data, always use email test@example.com and name Test Student")
2. Start a Claude Code session and perform tasks — Claude follows the instructions
3. Start a new Claude Code session (no prior conversation history)
4. Ask Claude to perform the same type of task
5. Claude ignores the CLAUDE.md instructions and uses default/improvised values instead

Expected Behavior

Claude Code should consistently follow all instructions in CLAUDE.md project files, regardless of whether there is prior conversation history. The instructions should be treated as binding project-level rules.

Actual Behavior

Claude intermittently ignores CLAUDE.md instructions, especially:

• Specific test data requirements (emails, names) that must be used for test generation
• The instructions are read and acknowledged but not reliably applied during task execution

Impact

Users rely on CLAUDE.md to encode project-specific rules that prevent mistakes. When these rules are silently ignored, it leads to:

• Wasted time correcting avoidable errors
• Loss of trust in the tool's reliability
• Frustration when the same mistakes recur across sessions

Environment

• Claude Code CLI (VSCode extension)
• macOS