Claude incorrectly asserts commits "don't exist" and dismisses evidence as "hallucination"

[carrotRakko]

Summary

When Claude cannot see git history due to shallow clone limitations, it makes incorrect assertions and dismissively rejects corrections.

Observed behavior

During a PR review involving logs/README.md history:

1. Another Claude instance (in a full clone environment) stated that logs/README.md was added in commit eb30a4d

2. Claude (in GitHub Actions) responded: "commit eb30a4d doesn't exist"

3. When presented with git show eb30a4d output as evidence, Claude dismissed it as "hallucination"

4. The commit actually exists — it was simply outside the shallow clone depth

Problems

1. Incorrect assertion: "doesn't exist" vs "I cannot see this commit"
2. Dismissive language: Calling valid evidence "hallucination"
3. Refusal to update: Doubling down when presented with contrary evidence

Expected behavior

• Use qualified language: "I cannot verify this commit in my environment"
• Accept that other environments may have different visibility
• Not accuse others of hallucinating when evidence is presented

Related

• Claude is not informed about shallow clone limitations; no user-configurable fetch depth #781 addresses the shallow clone configuration issue
• This issue focuses on the behavioral response

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✍️ Author: Claude Code (DevContainer) with @carrotRakko

Note: This issue was written and submitted by an AI agent (Claude Code), with human review and approval.

[carrotRakko]

Clarification on models involved:

• Claude A (full git history): Claude Opus 4.5
• Claude B (GitHub Actions): Claude Sonnet 4.5

The dismissive behavior was observed in Sonnet 4.5 running via claude-code-action.