fix: Claude fails to post review comment when markdown contains special characters

[Soumyadipgithub]

Problem

When Claude generates a code review containing markdown formatting (code blocks, backticks, inline code), the gh pr comment --body "..." shell command breaks due to special character escaping. Claude retries multiple times with different formats, wastes API turns, and eventually posts a degraded plain-text version.

Evidence

PR: coloredcow-admin/coloredcow#1152
Workflow Run: Run 23399208437 (08:29 UTC, 22 March 2026)

What happened step by step

Claude generated a well-formatted review with markdown headers, code blocks, and backticks. Then tried to post it:

Attempt	Command	Result
1	gh pr comment --body "..." with escaped backticks	Denied — shell parsing broke
2	Write to a temp file first	Denied — Write tool not in allowed-tools
3	cat << 'EOF' | gh pr comment --body-file -	Denied — didn't match allowed-tools pattern
4	gh pr comment --body "..." with different escaping	Denied — still broke
5	gh pr comment -b 'short plain text'	Worked — but all formatting stripped

Impact

• Review posted but degraded quality — no markdown, no code blocks, just a single paragraph
• Cost $0.22 instead of ~$0.10 (26 turns instead of ~6) due to retries
• Developer gets a less useful review

Comparison

What Claude wanted to post (from logs):

## Code Review Summary

### Critical Issues
None identified.

### Suggestions
**robots.txt:41** — Minor inconsistency...
**includes/ai-crawler-logger.php:145-147** — Inline styles...

What actually got posted (after 5 retries):

Code Review Summary - Critical Issues: None identified. - Suggestions: robots.txt:41 Minor bot name inconsistency. includes/ai-crawler-logger.php:145-147 Inline styles violate CLAUDE.md hard rule...

Root Cause

The prompt in claude-code-review.yml says:

"Create ONE single comment with your complete review"

But doesn't tell Claude how to post it safely. Claude defaults to gh pr comment --body "..." which breaks when the review contains backticks, code blocks, or other shell-special characters.

File Reference

• .github/workflows/claude-code-review.yml — the prompt input default value
• For More details, check this doc file.