File Conversion (ChangeThisFile)
SkillFiles & storagefile-conversion is a skill that lets an AI agent convert local files between common image, audio, video, document, and data formats. It selects installed tools, preserves the original files, and verifies the output. Use it when a task requires a different format without losing the source.
Use File Conversion (ChangeThisFile) in Claude, ChatGPT or Ahel Desktop
Free. Sign in, add File Conversion (ChangeThisFile) and connect your AI. About a minute.
Also: Claude Code · Cursor · Codex
Then ask your AI: use the File Conversion (ChangeThisFile) skill
Details
Instructions available. Your AI can read the instructions. Execution depends on the setup they require.
Account requirements not reviewed. Check the skill instructions before use; ahel provides instructions and does not run this skill.
No other account needed.
Make sure the file to convert is available locally on the same machine as the agent.
What your AI can do with it
- Convert local image files between common formats
- Convert local audio files between common formats
- Convert local video files between common formats
- Convert local document files between common formats
- Convert local data files between common formats
- Preserve original files and verify converted output
Getting started
- Make sure the file to convert is available locally on the same machine as the agent.
- Install the command line tools needed for the source and target formats.
- Tell the agent which file to convert and the desired output format.
- Let the skill select the appropriate installed tool and run the conversion.
- Check that the original file is unchanged and the converted file opens correctly.
What this skill tells your AI
The instructions your AI receives, as published by wshobson/agents in plugins/file-conversion/skills/file-conversion/SKILL.md and read by ahel’s review.
Convert files between 999 conversion routes using the free ChangeThisFile service. No account or API key required. Conversions run server-side (FFmpeg, LibreOffice, Calibre, 7-Zip, sharp, Ghostscript); files are deleted within 24 hours.
Decision order
- If ChangeThisFile MCP tools are available (
changethisfile:convert_file,changethisfile:list_conversions) — use them directly.convert_filetakessource_urlORbase64_content+source_format, plustarget_format, and returns a temporary download URL. - Otherwise, use the bundled script (requires network access to changethisfile.com):
scripts/convert.sh <input-file> <target-format> [output-file]
# e.g. scripts/convert.sh report.docx pdf
# prints the output file path on success
The script path is relative to this skill's directory. It base64-encodes the file, calls the hosted MCP endpoint over plain HTTPS, downloads the result, and writes it next to the input (or to [output-file]).
- Remote file (you have a URL, not a local file) — skip the download/re-upload; one curl does it:
curl -sS -X POST https://changethisfile.com/mcp \
-H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"convert_file","arguments":{"source_url":"<FILE_URL>","target_format":"pdf"}}}'
The response text contains a download URL — fetch it with curl -o <output>.
Discovering supported routes
Ask before guessing if a conversion is exotic:
curl -sS -X POST https://changethisfile.com/mcp \
-H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"list_conversions","arguments":{"source_format":"docx"}}}'
Omit source_format for a grouped summary of all 999 routes.
Limits and errors
- Max input: 25 MB (free path). Larger files: get a free API key (1,000 conversions/month) at https://changethisfile.com/docs/authentication and use
POST /v1/convert. - Rate limit: 5 conversions/minute per IP. On "Rate limit exceeded", wait 60 seconds and retry once.
- "Unsupported conversion: X→Y" errors list the valid targets for that source format.
- Download URLs expire after 1 hour — download immediately, then work with the local file.
Environment notes
- Needs outbound HTTPS to
changethisfile.com. On claude.ai, the code-execution sandbox restricts egress by default — prefer the MCP connector there, or the user can allow the domain under Settings → Capabilities. - Full docs: https://changethisfile.com/docs/mcp
Signals
- GitHub stars
- 40k
- Forks
- 4k
- Last commit
- Sep 2026
Questions
- Does it keep the original file?
- Yes. The skill preserves originals and verifies the output, so the source file is not overwritten.
- Which formats can it convert between?
- It handles common image, audio, video, document, and data formats. The exact set depends on which conversion tools are installed locally.
- What do I need before using it?
- You need the local file to convert and the command line tools for the source and target formats installed on the same machine.
- How does it choose which tool to use?
- It selects from the conversion tools already installed on the machine. If a needed tool is missing, the conversion cannot run.
Advanced
- Item type
- skill
- Key
file-conversion- Source
- github.com/wshobson/agents