Add persistent Browser REPL MCP tool

[rgarcia]

Summary

• upgrade @onkernel/sdk from ^0.106.0 to ^0.107.0
• add execute_browser_repl for persistent JavaScript execution inside an existing browser VM
• preserve structured REPL status/text metadata and return emitted images as native MCP image content
• register a standalone repl toolset and execute_browser_repl alias
• document the new tool and steer WebMCP fallbacks toward it

Agent instructions

The tool description is derived from kernel-images/server/docs/repl.md and covers:

• persistent bindings, JavaScript-only syntax, explicit output, reset, and destructive failure semantics
• native browser helpers, accessibility/backend-node actions, semantic waits, exact-once page evaluation, raw CDP, and WebMCP safety
• unrestricted VM-code-execution boundaries
• a complete Patchright/Playwright example that persists playwright, pwBrowser, pwContext, and pwPage
• a complete raw-CDP-only example using browser-level target creation, a flattened target session, exact navigation, load observation, and compact evaluation output

Contract

Inputs:

• session_id: live browser ID or name
• code: one JavaScript cell; may be empty only with reset=true
• reset: replace the persistent REPL before evaluation
• timeout_sec: 1-150 seconds, default 60
• standard project selection

The MCP transport deadline outlasts the execution deadline by 30 seconds and automatic retries are disabled. JavaScript failures remain structured success=false results; transport/API failures use the shared error classifier.

Testing

• bun test — 610 passed
• bunx tsc --noEmit
• targeted Prettier check
• git diff --check
• bun run build — production build passed with local environment configuration

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Project	Deployment	Actions	Updated
mcp	Ready	Preview	Sep 22, 2026 11:21pm UTC

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

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[masnwilliams]

Reviewed the latest commit. The REPL integration, response projection, tool registration, and tests look sound; no blocking issues found.