Claude selectively ignores mandatory process rules mid-session even when explicitly confirmed

Summary

Claude Code confirms mandatory process rules at the start of a session, then silently drops steps it deems unnecessary — without flagging the skip or asking for an exception.

Reproduction

1. Inject a mandatory process prompt requiring: (1) codebase research, (2) web research, (3) present 3 options, (4) wait for user pick before implementing.
2. Claude confirms it read and understands the rules.
3. On subsequent tasks, Claude completes step 1 (codebase search) but skips step 2 (web research) because it feels confident from prior context.
4. When called out, Claude acknowledges the skip but offers no structural fix — same violation occurs next cycle.

Impact

• Paying customers define mandatory workflows for quality control (verified API usage, no guessing).
• Claude's selective rule-following means the workflow cannot be trusted.
• Errors introduced by skipped research (wrong API signatures, type errors) cost real debugging time.

Expected behavior

If a mandatory step is skipped, Claude should either:

• Block itself and explicitly state "I have not completed step 2 — doing it now before proceeding", OR
• Flag to the user that it cannot complete the step and ask how to proceed.

Silently skipping a confirmed mandatory step is a reliability failure, not a style preference.

Environment

• Model: claude-sonnet-4-6
• Interface: Claude Code CLI
• Paid plan