[BUG] desktop.ini is ingested as a rule

[winne617]

Problem (one or two sentences)

System files like desktop.ini (Windows) are added to the system prompt, polluting it with gibberish.

Context (who is affected and when)

Roo Code currently excludes some system files like .DS_Store and Thumbs.db when reading the .roo/rules/ directory. On Windows, desktop.ini is frequently generated in these folders and is currently being read as a custom instruction, polluting the system prompt with gibberish.
Please add desktop.ini to the default exclusion list.
Or even better: maybe we could define some file types ourselves ...?

thx a lot;)

Reproduction steps

Have a Windows PC, put a desktop.ini in the rules folder and read the resulting system prompt. Easy.

Expected result

no ini read

Actual result

ini read

Variations tried (optional)

No response

App Version

2026-02-10

API Provider (optional)

None

Model Used (optional)

No response

Roo Code Task Links (optional)

No response

Relevant logs or errors (optional)

[roomote]

I've analyzed this issue and here's my proposed implementation plan:

The shouldIncludeRuleFile function in src/core/prompts/sections/custom-instructions.ts maintains a cachePatterns list used to exclude system/cache files from being read as rules. It already excludes .DS_Store and Thumbs.db, but desktop.ini is missing.

Changes:

1. src/core/prompts/sections/custom-instructions.ts -- Add "desktop.ini" to the cachePatterns array in shouldIncludeRuleFile() as an exact-match entry (same style as Thumbs.db), plus "*.ini" as a wildcard to cover .ini files more broadly since they are Windows configuration files and not rule content.

   Actually, on reflection, *.ini would be too broad -- users might intentionally put .ini-formatted rule files in their rules directory. So I'll just add "desktop.ini" as an exact basename match, consistent with how Thumbs.db is handled.

2. src/core/prompts/sections/__tests__/custom-instructions.spec.ts -- Update the existing "should filter out cache files" test to include desktop.ini in the mock file list and verify it gets excluded.

This is a minimal, targeted fix that matches the existing pattern in the codebase.

Please mention @roomote in a comment saying that you approve this plan, and I'll proceed with the implementation.

[winne617]

@roomote this sounds amazing. please apply.

[roomote]

I've seen your comment and will proceed with the implementation. I'll add desktop.ini to the exclusion list in shouldIncludeRuleFile and update the tests. I'll open a draft PR shortly to share progress.

[roomote]

Opened a draft PR with my attempt at addressing this: #11384

Added desktop.ini to the exclusion list in shouldIncludeRuleFile(), matching the existing pattern for Thumbs.db. Tests updated and passing. Feedback welcome!