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[UPDATE PRIMITIVE] Fix markdown injection and platform-dependent path tests in prompt handlers#162

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data-douser merged 4 commits intodd/improve-error-handling-relative-path-supportfrom
copilot/sub-pr-153
Mar 23, 2026
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[UPDATE PRIMITIVE] Fix markdown injection and platform-dependent path tests in prompt handlers#162
data-douser merged 4 commits intodd/improve-error-handling-relative-path-supportfrom
copilot/sub-pr-153

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Copilot AI commented Mar 23, 2026

User-supplied path values and Zod validation error details were embedded raw into markdown code spans, allowing backticks or newlines in inputs to corrupt prompt output formatting. Test assertions used POSIX-specific path fragments that would fail on Windows after relative-to-absolute path resolution.

📝 Update Information

Primitive Details

  • Type: Both (implementation + tests)
  • Name: workflow-prompts (resolvePromptFilePath, formatValidationError, markdownInlineCode)
  • Update Category: Bug Fix, Code Quality

⚠️ CRITICAL: PR SCOPE VALIDATION

ALLOWED FILES:

  • Server implementation files (server/src/**/*.ts)
  • Updated or new test files (server/test/**/*.ts)

🚫 FORBIDDEN FILES: None included.


🛑 MANDATORY PR VALIDATION CHECKLIST

  • ONLY server implementation files are included
  • NO temporary or output files are included
  • NO unrelated configuration files are included
  • ALL existing tests continue to pass
  • NEW functionality is properly tested

  • Impact Scope: Localized

Update Metadata

  • Breaking Changes: No
  • API Compatibility: Maintained (new markdownInlineCode export added)
  • Performance Impact: Neutral

🎯 Changes Description

Current Behavior

resolvePromptFilePath embeds the raw filePath and absolutePath strings in backtick code spans. formatValidationError embeds issue.received raw. Any value containing a backtick prematurely closes the code span; newlines break the markdown line. Test assertions like toContain('path/to/mydb') pass on POSIX but fail on Windows once paths are resolved to OS-native absolute form.

Updated Behavior

A markdownInlineCode() helper wraps user-supplied strings in a CommonMark-compliant backtick fence whose length exceeds the longest backtick run in the value, so the original string is preserved without mutation. All newline sequences (CR, LF, CRLF) are replaced with a single space so the returned span is always a single line. Path-fragment test assertions use basename-only tokens. createSafePromptHandler error-path test names explicitly state what they are validating.

Motivation

Malformed user input (e.g. a filename containing backticks or newlines) could silently corrupt the structured markdown returned to the LLM. Replacing backticks with apostrophes (a prior approach) caused information loss. Normalising CRLF/CR to LF (an intermediate approach) still allowed literal \n to break surrounding markdown formatting. Test suite was implicitly POSIX-only.

🔄 Before vs. After Comparison

Functionality Changes

// BEFORE
warning: `⚠ **File path** \`${filePath}\` **does not exist.** Resolved to: \`${absolutePath}\``,

// AFTER — backtick fence length chosen per CommonMark spec; newlines replaced with space; original backtick content preserved
export function markdownInlineCode(value: string): string {
  // Replace all newline sequences with a space — inline code spans cannot
  // span lines, and keeping literal newlines would break surrounding markdown.
  const normalized = value.replace(/\r\n|\r|\n/g, ' ');

  let maxRun = 0;
  let currentRun = 0;
  for (const ch of normalized) {
    if (ch === '`') { currentRun += 1; if (currentRun > maxRun) maxRun = currentRun; }
    else { currentRun = 0; }
  }
  const fence = '`'.repeat(maxRun + 1);
  return `${fence}${normalized}${fence}`;
}
warning: `⚠ **File path** ${markdownInlineCode(filePath)} **does not exist.** Resolved to: ${markdownInlineCode(absolutePath)}`,

// formatValidationError — same treatment for issue.received
// BEFORE
`- **\`${field}\`**: received \`${String(issue.received)}\` — ...`
// AFTER
`- **\`${field}\`**: received ${markdownInlineCode(String(issue.received))} — ...`

API Changes

No schema changes. markdownInlineCode is exported as a new testable utility.

Output Format Changes

Warning and validation-error messages are semantically unchanged; values containing backticks are now displayed using a longer fence (e.g. a`b ) rather than corrupting the markdown structure or mutating the value. Values containing newlines have the newlines replaced with spaces so the inline code span is always single-line.

🧪 Testing & Validation

Test Coverage Updates

  • Existing Tests: All 1038 server unit tests pass
  • New Test Cases: Added 6 unit tests for markdownInlineCode (plain text, single backtick, double-backtick run, CRLF/CR/LF→space, backtick-only value)
  • Regression Tests: Added regression test for formatValidationError with a backtick in issue.received; added regression test for resolvePromptFilePath warning with a backtick in the path; path-fragment assertions made platform-agnostic
  • Edge Case Tests: Test names clarified to distinguish createSafePromptHandler wrapper behavior from MCP SDK protocol-layer validation

Validation Scenarios

  1. Backward Compatibility: Fence-wrapping is a display-only change; downstream tools still receive the full resolved path via resolvedPath.
  2. New Functionality: markdownInlineCode covers single-backtick, multi-backtick runs, and all newline variants (\n, \r\n, \r) — replacing newlines with spaces and preserving all other content.
  3. Error Handling: formatValidationError now safe for any issue.received value.
  4. Performance: Pure string scan + fence construction, no measurable impact.

Test Results

  • Unit Tests: All pass (1038/1038)
  • Integration Tests: Pre-existing codeql_pack_install failure unrelated to these changes
  • Manual Testing: N/A (pure string wrapping)
  • Performance Testing: No regressions detected

📋 Implementation Details

Files Modified

  • Core Implementation: server/src/prompts/workflow-prompts.ts
  • Tests: server/test/src/prompts/workflow-prompts.test.ts

Code Changes Summary

  • Error Handling: User-supplied strings in markdown warning/error messages wrapped with CommonMark-compliant fence; all newlines replaced with spaces for guaranteed single-line output
  • Type Safety: No changes
  • Input Validation: markdownInlineCode applied at interpolation sites

Dependencies

  • No New Dependencies: Uses only built-in string methods

🔍 Quality Improvements

Bug Fixes (if applicable)

  • Issue: Backticks or newlines in user-supplied file paths corrupted markdown code spans in prompt output; normalising CRLF/CR to LF still left literal \n in the output which could break surrounding markdown formatting
  • Root Cause: Raw string interpolation into fixed-length backtick-delimited markdown code spans; incomplete newline handling
  • Solution: markdownInlineCode() uses a CommonMark-compliant fence whose length exceeds any internal backtick run, and replaces all newline sequences with a space, guaranteeing single-line output while preserving the original content
  • Prevention: All future interpolation into markdown code spans should use this helper

Code Quality Enhancements

  • Readability: Test names now explicitly state the behavior under test (createSafePromptHandler wrapper vs SDK validation); newline test updated to assert space-replacement rather than LF-normalisation
  • Maintainability: Centralized inline-code wrapping logic in a single exported helper
  • Testability: Path assertions are platform-agnostic; markdownInlineCode is exported and independently tested

🔗 References

Related Issues/PRs

🚀 Compatibility & Migration

Backward Compatibility

  • Fully Compatible: No breaking changes

API Evolution

  • Enhanced Parameters: New exported markdownInlineCode utility
  • Maintained Contracts: Core API contracts preserved

👥 Review Guidelines

For Reviewers

Please verify:

  • ⚠️ SCOPE COMPLIANCE: PR contains only server implementation files
  • ⚠️ NO UNRELATED FILES: No temporary, output, or unrelated files
  • ⚠️ BACKWARD COMPATIBILITY: Existing functionality preserved
  • Functionality: markdownInlineCode correctly handles backtick runs of all lengths and replaces all newline variants with a space
  • Test Coverage: 1038/1038 unit tests pass; regression tests added for backtick/newline edge cases; path assertions are platform-agnostic
  • Code Quality: Helper is minimal, well-documented, and independently testable

Testing Instructions

npm run build-and-test   # from repo root
# or just server unit tests:
cd server && npm test

📊 Impact Assessment

Server Impact

  • Startup Time: No impact
  • Runtime Stability: No impact
  • Resource Usage: Negligible
  • Concurrent Usage: Safe (pure functions)

AI Assistant Impact

  • Improved Reliability: LLM no longer receives malformed markdown when user inputs contain backticks or newlines; original backtick content preserved in output
  • Enhanced User Experience: Error messages render correctly regardless of input content

🔄 Deployment Strategy

Rollout Considerations

  • Safe Deployment: Localized display-only change; no behavioral impact on tool execution

Update Methodology: This update follows best practices:

  1. ✅ Comprehensive backward compatibility analysis
  2. ✅ Thorough testing of all changes
  3. ✅ Performance impact assessment
  4. ✅ Clear documentation of changes
  5. ✅ Robust error handling improvements
  6. ✅ Maintained code quality standards

⚡ Quickly spin up Copilot coding agent tasks from anywhere on your macOS or Windows machine with Raycast.

…ndlers

- Add sanitizeForInlineCode() helper to escape backticks and newlines in user-supplied values embedded in markdown code spans
- Apply sanitizer to resolvePromptFilePath 'does not exist' warning (filePath and absolutePath)
- Apply sanitizer to formatValidationError issue.received display
- Fix POSIX path separator assumptions in tests: use basename only ('mydb', 'database')
- Rename createSafePromptHandler tests to clarify they validate the handler wrapper, not MCP SDK validation

Co-authored-by: data-douser <70299490+data-douser@users.noreply.github.com>
Agent-Logs-Url: https://github.com/advanced-security/codeql-development-mcp-server/sessions/2660567b-5822-4505-91c2-37fe3ef00f4e
Copilot AI changed the title [WIP] Improve prompt error handling and relative path support [UPDATE PRIMITIVE] Fix markdown injection and platform-dependent path tests in prompt handlers Mar 23, 2026
Copilot AI requested a review from data-douser March 23, 2026 19:47
@data-douser data-douser marked this pull request as ready for review March 23, 2026 19:48
@data-douser data-douser requested review from a team and enyil as code owners March 23, 2026 19:48
@data-douser data-douser requested a review from Copilot March 23, 2026 19:48
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Pull request overview

Fixes markdown formatting corruption in prompt warnings/errors by sanitizing user-supplied values embedded in inline code spans, and makes path-related tests platform-agnostic (Windows-safe).

Changes:

  • Add sanitizeForInlineCode() and apply it to interpolated file paths and enum “received” values.
  • Update tests to assert on basename tokens instead of POSIX path fragments.
  • Update built server/dist bundle with the new sanitization logic.

Reviewed changes

Copilot reviewed 2 out of 4 changed files in this pull request and generated 3 comments.

File Description
server/src/prompts/workflow-prompts.ts Adds and uses inline-code sanitization for markdown output.
server/test/src/prompts/workflow-prompts.test.ts Adjusts assertions to be platform-agnostic and clarifies test names.
server/dist/codeql-development-mcp-server.js Regenerated build output reflecting the sanitization changes.

…eCode

- markdownInlineCode() uses a fence length = maxRun+1 per CommonMark spec,
  preserving the original string (no information loss from backtick→apostrophe)
- Normalises CR/CRLF to LF before wrapping (inline spans can't span lines)
- Export markdownInlineCode for testability
- Add 6 unit tests for markdownInlineCode (plain text, single/double backtick,
  CRLF normalisation, backtick-only values)
- Add regression test for formatValidationError with backtick in received value
- Add regression test for resolvePromptFilePath warning with backtick in path

Co-authored-by: data-douser <70299490+data-douser@users.noreply.github.com>
Agent-Logs-Url: https://github.com/advanced-security/codeql-development-mcp-server/sessions/ec7c534b-93ac-40e5-bcb6-023bc7496940
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Pull request overview

Copilot reviewed 2 out of 4 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

server/src/prompts/workflow-prompts.ts:154

  • resolvePromptFilePath() now uses markdownInlineCode() for the "does not exist" warning, but the earlier "is not a valid file URI" warning still wraps the raw filePath in a single-backtick code span. That path can also contain backticks/newlines, so the same markdown-injection issue remains for invalid file:// inputs. Apply markdownInlineCode() there as well for consistent sanitization.
    return {
      resolvedPath: absolutePath,
      warning: `⚠ **File path** ${markdownInlineCode(filePath)} **does not exist.** Resolved to: ${markdownInlineCode(absolutePath)}`,
    };

@data-douser
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@copilot apply changes based on the comments in this thread

…e output

Replace \r\n, \r, and \n with a space (not just normalize CRLF to LF) so
the returned inline code span never contains a literal newline character.
Update docstring and test to reflect space-replacement behavior.

Co-authored-by: data-douser <70299490+data-douser@users.noreply.github.com>
Agent-Logs-Url: https://github.com/advanced-security/codeql-development-mcp-server/sessions/87cfd54e-9d66-4871-a581-601aff3c6c8d
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Copilot AI commented Mar 23, 2026

@copilot apply changes based on the comments in this thread

Done in commit d49aff0. markdownInlineCode now replaces all newline sequences (\r\n, \r, \n) with a single space so the returned span is always single-line. The docstring and the corresponding test were updated to match (expecting 'a b' instead of 'a\nb').

@data-douser data-douser merged commit 0c0a715 into dd/improve-error-handling-relative-path-support Mar 23, 2026
@data-douser data-douser deleted the copilot/sub-pr-153 branch March 23, 2026 20:36
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3 participants