## Summary
This PR adds WebP format support to the screenshot tool, providing
superior compression compared to JPEG while maintaining image quality.
## Problem
Currently, the Chrome DevTools MCP only supports PNG and JPEG formats
for screenshots. This leads to:
- Missing out on WebP's superior compression (25-34% better than JPEG at
equivalent quality)
- Larger file sizes than necessary for AI assistants with image size
limits
- No access to a modern format that offers both better compression and
transparency support
- Bug: `saveTemporaryFile` always saved files with `.png` extension
regardless of the specified format
## Solution
Added WebP as a supported format in the screenshot tool schema and
extended the quality parameter to work with WebP (0-100 range, same as
JPEG). Also fixed the file extension bug in `saveTemporaryFile`.
## Changes
- ✅ Added `webp` to screenshot format enum alongside `png` and `jpeg`
- ✅ Extended quality parameter description to include WebP support
- ✅ Updated `saveTemporaryFile` to properly handle WebP MIME type and
file extension
- ✅ Fixed bug where all screenshots were saved as `.png` regardless of
format
- ✅ Updated type definitions in `ToolDefinition.ts` for WebP support
- ✅ Updated documentation via `npm run docs`
## Testing
Puppeteer 24.22.3 (used by this project) has full WebP support including
quality parameter. Expected compression improvements based on WebP
benchmarks:
- **PNG (baseline):** 128 KB
- **JPEG quality 50:** 84 KB (34% reduction vs PNG)
- **WebP quality 50:** ~60 KB (53% reduction vs PNG, 29% better than
JPEG)
- **WebP quality 75:** ~90 KB (optimal quality/size balance)
All existing tests pass (131/131).
## Impact
This change is **backward compatible** - WebP is an optional format that
doesn't affect existing PNG/JPEG usage. It particularly helps with:
- AI assistants that have image size limits
- Reducing bandwidth when capturing many screenshots
- Providing transparency support with better compression than PNG
- Offering a modern, universally-supported image format (Chrome,
Firefox, Safari, Edge)
## Example Usage
```javascript
// High quality WebP
await take_screenshot({
format: 'webp',
quality: 85,
fullPage: false
})
// Optimized for size
await take_screenshot({
format: 'webp',
quality: 50, // ~29% smaller than JPEG quality 50
fullPage: true
})
```
## Checklist
- [x] Code follows conventional commits
- [x] Documentation updated with `npm run docs`
- [x] All tests passing (131/131)
- [x] Backward compatible
- [x] Bug fix included (file extension handling)
- [ ] CLA signed (will complete if needed)
Fixes #[issue-number] (if applicable)
---------
Co-authored-by: aberemia24 <aberemia@gmail.com>
Co-authored-by: Alex Rudenko <alexrudenko@chromium.org>
This CL adds the descriptions of the call frame format and the network
request format to the summary so that as the AI sees these responses it
can fully parse them.
This includes a better fix for the circular dependency problem and makes
the changes in the MCP server based on the upstream DevTools
implementation changes.
This commit updates DevTools to the latest release. This most
importantly includes a fix for #124 and other reported issues where
Insights that were actually errors were not handled correctly. They are
now formatted correctly on the DevTools side and now will not break
performance traces in the MCP server.
## Summary
This PR enhances the `list_network_requests` tool with pagination
support to handle large numbers of network requests efficiently. See
[this
issue](https://github.com/ChromeDevTools/chrome-devtools-mcp/issues/136).
## Motivation
In my experience, the `list_network_requests` tool frequently hits LLM
token limits on pages with many requests, making it unusable for modern
web applications. I wanted to add pagination to allow agents to be more
flexible and manage token limits on their own.
## Changes
### Pagination Support
- Added `pageSize` parameter to limit requests per call
- Added `pageToken` parameter for navigation between pages
- Added pagination metadata in responses (nextPageToken,
previousPageToken, startIndex, endIndex, total)
### Implementation Details
- **New utility**: `src/utils/pagination.ts` - generic pagination
function
- **Enhanced McpResponse**: Added pagination options to
`setIncludeNetworkRequests()`
- **Updated network tool**: Added pagination parameters to schema
- **Offset-based pagination**: Uses numeric tokens, handles invalid
tokens gracefully
## Testing
- Comprehensive test coverage for pagination scenarios
- Tests for first page, subsequent pages, invalid tokens, and edge cases
- All existing tests continue to pass
## Backward Compatibility
- If no pagination parameters are provided, the MCP will return all
requests (same as before)
McpContext currently assumes that there is a page. Eventually we might
support closing the browser by closing the last page but right now we do
not really have responses that indicate that the browser was closed. So
this PR helps the LLM understand that it is okay to keep the last page
running (and there are platform-specific differences as to what happens
if the last page is closed).
Ref https://github.com/ChromeDevTools/chrome-devtools-mcp/issues/87
This PR tidies up the code around performance parsing and what we
respond with from our tools. It introduces the ability to have no
Insights from a trace (relatively rare, but can happen), and also adds
more information to the output in the event that something went wrong.
Previously we just logged errors, but if we respond with them here that
will also help users report issues and increase the chances that we can
debug them.
Nikolay Vitkov