file-conversion
Convert files between formats — PDF to Word, HEIC to JPG, MP4 to MP3, CSV to JSON, EPUB to MOBI, and 999 total routes across images, video, audio, documents, data, fonts, ebooks, and archives. Free via changethisfile.com, no API key or signup. Use when the user needs a file converted to a different format.
git clone --depth 1 https://github.com/wshobson/agents /tmp/file-conversion && cp -r /tmp/file-conversion/plugins/file-conversion/skills/file-conversion ~/.claude/skills/file-conversionSKILL.md
# File Conversion (ChangeThisFile)
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
1. **If ChangeThisFile MCP tools are available** (`changethisfile:convert_file`, `changethisfile:list_conversions`) — use them directly. `convert_file` takes `source_url` OR `base64_content` + `source_format`, plus `target_format`, and returns a temporary download URL.
2. **Otherwise, use the bundled script** (requires network access to changethisfile.com):
```bash
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]`).
3. **Remote file (you have a URL, not a local file)** — skip the download/re-upload; one curl does it:
```bash
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:
```bash
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/mcpTest web applications with screen readers including VoiceOver, NVDA, and JAWS. Use when validating screen reader compatibility, debugging accessibility issues, or ensuring assistive technology support.
Conduct WCAG 2.2 accessibility audits with automated testing, manual verification, and remediation guidance. Use when auditing websites for accessibility, fixing WCAG violations, or implementing accessible design patterns.
Coordinate parallel code reviews across multiple quality dimensions with finding deduplication, severity calibration, and consolidated reporting. Use this skill when organizing multi-reviewer code reviews, calibrating finding severity, or consolidating review results.
Debug complex issues using competing hypotheses with parallel investigation, evidence collection, and root cause arbitration. Use this skill when debugging bugs with multiple potential causes, performing root cause analysis, or organizing parallel investigation workflows.
Coordinate parallel feature development with file ownership strategies, conflict avoidance rules, and integration patterns for multi-agent implementation. Use this skill when decomposing a large feature into independent work streams, when two or more agents need to implement different layers of the same system simultaneously, when establishing file ownership to prevent merge conflicts in a shared codebase, when designing interface contracts so parallel implementers can build against each other's APIs before they are ready, or when deciding whether to use vertical slices versus horizontal layers for a full-stack feature.
Decompose complex tasks, design dependency graphs, and coordinate multi-agent work with proper task descriptions and workload balancing. Use this skill when breaking down work for agent teams, managing task dependencies, or monitoring team progress.
Structured messaging protocols for agent team communication including message type selection, plan approval, shutdown procedures, and anti-patterns to avoid. Use this skill when establishing communication norms for a newly spawned team, when deciding whether to send a direct message or a broadcast, when a team-lead needs to review and approve an implementer's plan before work begins, when orchestrating a graceful team shutdown after all tasks are complete, or when debugging why teammates are not coordinating correctly at integration points.
Design optimal agent team compositions with sizing heuristics, preset configurations, and agent type selection. Use this skill when deciding how many agents to spawn for a task, when choosing between a review team versus a feature team versus a debug team, when selecting the correct subagent_type for each role to ensure agents have the tools they need, when configuring display modes (tmux, iTerm2, in-process) for a CI or local environment, or when building a custom team composition for a non-standard workflow such as a migration or security audit.