warehack.ing/playwright-mcp
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feat: add snapshot size limits and optional snapshots to fix token overflow

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Implements comprehensive solution for browser_click and other interactive tools
returning massive responses (37K+ tokens) due to full page snapshots.

Features implemented:
1. **Snapshot size limits** (--max-snapshot-tokens, default 10k)
   - Automatically truncates large snapshots with helpful messages
   - Preserves essential info (URL, title, errors) when truncating
   - Shows exact token counts and configuration suggestions

2. **Optional snapshots** (--no-snapshots)
   - Disables automatic snapshots after interactive operations
   - browser_snapshot tool always works for explicit snapshots
   - Maintains backward compatibility (snapshots enabled by default)

3. **Differential snapshots** (--differential-snapshots)
   - Shows only changes since last snapshot instead of full page
   - Tracks URL, title, DOM structure, and console activity
   - Significantly reduces token usage for incremental operations

4. **Enhanced tool descriptions**
   - All interactive tools now document snapshot behavior
   - Clear guidance on when snapshots are included/excluded
   - Helpful suggestions for users experiencing token limits

Configuration options:
- CLI: --no-snapshots, --max-snapshot-tokens N, --differential-snapshots
- ENV: PLAYWRIGHT_MCP_INCLUDE_SNAPSHOTS, PLAYWRIGHT_MCP_MAX_SNAPSHOT_TOKENS, etc.
- Config file: includeSnapshots, maxSnapshotTokens, differentialSnapshots

Fixes token overflow errors while providing users full control over
snapshot behavior and response sizes.

Co-Authored-By: Claude <noreply@anthropic.com>
This commit is contained in:
Ryan Malloy 2025-08-22 07:54:36 -06:00
parent 7d97fc3e3b
commit 574fdc4959
10 changed files with 301 additions and 67 deletions
Download patch file Download diff file Expand all files Collapse all files

7
src/program.ts
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@ -45,6 +45,9 @@ program
.option('--ignore-https-errors', 'ignore https errors')
.option('--isolated', 'keep the browser profile in memory, do not save it to disk.')
.option('--image-responses <mode>', 'whether to send image responses to the client. Can be "allow" or "omit", Defaults to "allow".')
.option('--no-snapshots', 'disable automatic page snapshots after interactive operations like clicks. Use browser_snapshot tool for explicit snapshots.')
.option('--max-snapshot-tokens <tokens>', 'maximum number of tokens allowed in page snapshots before truncation. Use 0 to disable truncation. Default is 10000.', parseInt)
.option('--differential-snapshots', 'enable differential snapshots that only show changes since the last snapshot instead of full page snapshots.')
.option('--no-sandbox', 'disable the sandbox for all process types that are normally sandboxed.')
.option('--output-dir <path>', 'path to the directory for output files.')
.option('--port <port>', 'port to listen on for SSE transport.')
@ -66,6 +69,10 @@ program
console.error('The --vision option is deprecated, use --caps=vision instead');
options.caps = 'vision';
}
// Handle negated boolean options
if (options.noSnapshots !== undefined)
options.includeSnapshots = !options.noSnapshots;
const config = await resolveCLIConfig(options);
const abortController = setupExitWatchdog(config.server);