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perf(cli): re-use MCPServer.from helpers for daemon by Lightning00Blade · Pull Request #2804 · ChromeDevTools/chrome-devtools-mcp · GitHub
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perf(cli): re-use MCPServer.from helpers for daemon - #2804

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  • Lower Memory & Process Overhead: Previously, running the CLI daemon spawned two separate Node.js processes (the daemon process + the child chrome-devtools-mcp server process). Running McpServer in-process halves the Node.js runtime footprint for the daemon.
  • Faster Daemon Startup & Tool Execution: Eliminates the latency of spawning a second Node.js process, performing the MCP initialization handshake over stdio pipes, and serializing/deserializing every tool request and response (including large screenshots or heap snapshot payloads) across an extra stdio IPC hop.
  • Simpler Process Lifecycle & Reliability: Removes an entire class of orphan-process and stdio pipe synchronization edge cases when the daemon starts, crashes, or shuts down.
  • Smaller Production Bundle (src/third_party): Because src/ no longer uses @modelcontextprotocol/client, Rollup no longer bundles the MCP client SDK or its client-only transports into build/src/third_party/index.js, and the ESLint restriction guarantees it stays out of production code.

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  • Update the process.on('unhandledRejection', ...) handler in src/daemon/daemon.ts (lines 316–319) to match src/bin/chrome-devtools-mcp-main.ts by only logging unhandled rejections unless process.env['CHROME_DEVTOOLS_MCP_CRASH_ON_UNCAUGHT'] === 'true', rather than calling void cleanup(1). Now that McpServer, BrowserManager, and Puppeteer run in-process inside daemon.ts, calling cleanup(1) on unhandledRejection will kill the daemon and close the browser on transient CDP or target-close rejections that the server previously survived.
  • Add await started; before checking if (!mcpServer) in the msg.method === 'invoke_tool' branch of handleRequest in src/daemon/daemon.ts, matching the stop and status branches. Because server.listen accepts connections on socketPath before await setupMCPServer() completes McpServer.from(), an invoke_tool request arriving during startup can otherwise fail with MCP server not initialized.
  • Add unit tests for McpServer.prototype.callTool (src/index.ts) covering unknown tool names, Zod schema validation failures, and valid tool execution. The new callTool method adds custom lookup and validation branches that bypass the MCP SDK server's request handler and currently lack direct unit test coverage.

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OrKoN commented Sep 23, 2026

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Maybe point #1 is a good reason to keep the separate process? 🤔

@Lightning00Blade Lightning00Blade changed the title performance(cli): re-use MCPServer.from helpers for daemon perf(cli): re-use MCPServer.from helpers for daemon Sep 23, 2026
@Lightning00Blade
Lightning00Blade force-pushed the remove-client-from-bundle branch from 062096c to 0988a7c Compare September 25, 2026 11:52
Comment thread src/utils/errorHandling.ts Resolved
@Lightning00Blade
Lightning00Blade force-pushed the remove-client-from-bundle branch from da13eb5 to 4c3a240 Compare September 28, 2026 13:48
@Lightning00Blade
Lightning00Blade added this pull request to the merge queue Sep 28, 2026
Merged via the queue into main with commit 89eb3d5 Sep 28, 2026
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@Lightning00Blade
Lightning00Blade deleted the remove-client-from-bundle branch September 28, 2026 14:39
OrKoN added a commit that referenced this pull request Oct 15, 2026
🤖 I have created a release *beep* *boop*
---


##
[1.11.0](chrome-devtools-mcp-v1.10.1...chrome-devtools-mcp-v1.11.0)
(2026-10-15)


### 🎉 Features

* add --file-navigations flag to reject file: URL navigations
([#2853](#2853))
([54cae57](54cae57))
* Add analyze_heapsnapshot_contexts MCP tool
([#2791](#2791))
([190aeee](190aeee))
* add ignoreCache option to performance_start_trace
([#2931](#2931))
([3467d40](3467d40))
* add maxNameLength truncation option to compare_heapsnapshots
([#3098](#3098))
([1e1c53e](1e1c53e))
* Add pagination to compare_heapsnapshots
([#3140](#3140))
([daebfd1](daebfd1))
* **config:** add ConfigWatcher to watch config file changes
([#3139](#3139))
([9171f77](9171f77))
* discover the config file in predefined locations
([#2876](#2876))
([02c0112](02c0112))
* implement ffmpeg-free screencast tools enabled by default
([#3123](#3123))
([8953ea5](8953ea5))
* reduce StaticText noise in text snapshots
([#2895](#2895))
([4441325](4441325))
* report pages opened by input actions
([#2679](#2679))
([28fb230](28fb230))
* resolve config defaults after merging CLI and config file
([#2849](#2849))
([bdeb70d](bdeb70d))
* return failing audits and DOM nodes inline from lighthouse_audit
([#2930](#2930))
([241fba5](241fba5))
* skip more redundant data in text snapshots
([#2896](#2896))
([b2f522c](b2f522c))
* support debugging WebMCP tools in third-party developer tools
([#2900](#2900))
([0db519f](0db519f))
* support emulating additional CSS media features
([#2929](#2929))
([69524f0](69524f0))
* support evaluating scripts from local files
([#2606](#2606))
([9cf47a4](9cf47a4))
* Support truncation in get_heapsnapshot_details
([#3137](#3137))
([f827e06](f827e06))
* Truncate long names by default to 100 characters
([#2893](#2893))
([5ddb0a3](5ddb0a3))


### 🛠️ Fixes

* account for scroll offsets in downscaled screenshots
([#2685](#2685))
([830c693](830c693))
* allow --categoryExtensions when connecting to an existing browser
([#3041](#3041))
([d250bc5](d250bc5))
* allow stopping the CLI if command fails
([#3088](#3088))
([77e238e](77e238e)),
closes
[#2982](#2982)
* avoid runtime title fetches
([#2883](#2883))
([04195d1](04195d1))
* better config support for chrome-devtools CLI
([#2819](#2819))
([9624e64](9624e64))
* clamp async stack trace separator repeat count
([#3035](#3035))
([93e06ab](93e06ab)),
closes
[#3031](#3031)
* **cli:** pass positional values starting with `-` through to tools
([#3084](#3084))
([9de05ae](9de05ae)),
closes
[#2984](#2984)
* **collectors:** ignore transient target errors when subscribing to
service workers
([#2888](#2888))
([551dd6c](551dd6c))
* **daemon:** bound browser shutdown and avoid watchFile timeout on stop
([#2887](#2887))
([f3db5e7](f3db5e7))
* **daemon:** keep fallback socket in private runtime dir
([#2766](#2766))
([871a37e](871a37e))
* **daemon:** verify process identity before treating PID file as active
([#3109](#3109))
([b608bed](b608bed))
* do not close a healthy browser when a tool call outlasts 60s
([#3149](#3149))
([39c7db1](39c7db1))
* ensure aggregate IDs in heap snapshots are deterministic
([#2923](#2923))
([e918c47](e918c47))
* escape client-supplied values in McpContext logs and errors
([#2832](#2832))
([efb0d02](efb0d02)),
closes
[#2831](#2831)
* fail fast on tool calls stuck after a dead browser connection
([#2699](#2699))
([2a7ef50](2a7ef50))
* harden third-party tool result serialization
([#2892](#2892))
([4418a7b](4418a7b))
* honor explicit --allowUnrestrictedPaths=false in CLI mode
([#3040](#3040))
([61fc362](61fc362))
* include errors in slim responses
([#3085](#3085))
([ee38097](ee38097))
* **input:** reject multiple file paths on single-file input in
upload_file
([#2995](#2995))
([#3135](#3135))
([e650843](e650843))
* list fresh page titles
([#3103](#3103))
([e717082](e717082))
* **memory:** reject contradictory pagination options in
take_heapsnapshot
([#3002](#3002))
([#3131](#3131))
([508126c](508126c))
* **network:** enforce URL policy across redirects
([#2767](#2767))
([274cd4c](274cd4c))
* pass categoryExtensions to the target filter when connecting
([#3047](#3047))
([4e90238](4e90238))
* **performance:** report an error when performance_stop_trace is called
with no active trace
([#3001](#3001))
([#3126](#3126))
([e170384](e170384))
* preserve HeapSnapshotManager across browser reconnects
([#3025](#3025))
([64388c6](64388c6))
* propagate failed responseFilePath write error instead of reporting
body unavailable
([#2957](#2957))
([#3119](#3119))
([3cee3bd](3cee3bd))
* **pwa:** wait for initial navigation on launch and retry transient
install error
([#2889](#2889))
([63010cb](63010cb))
* record screencast at the page's device pixel size
([#3155](#3155))
([62e2aa4](62e2aa4))
* reject --blockedUrlPattern/--allowedUrlPattern hostname regexp groups
([#2796](#2796))
([ae0aaef](ae0aaef))
* reject JSON arrays as 3p and WebMCP tool params
([#2785](#2785))
([c14e616](c14e616))
* reject named groups in URL patterns
([#2857](#2857))
([5b2c6f9](5b2c6f9))
* reject non-positive --viewport dimensions
([#2781](#2781))
([0ef528a](0ef528a))
* reject non-positive resize_page dimensions
([#2784](#2784))
([6ab6d35](6ab6d35))
* reject unrestricted paths with an explicit workspace
([#2858](#2858))
([45c1c6c](45c1c6c))
* report unknown page id before last-page guard in close_page
([#3042](#3042))
([bdc7e24](bdc7e24))
* round lighthouse category scores and show unscored categories as n/a
([#2924](#2924))
([7007680](7007680)),
closes
[#2915](#2915)
[#2916](#2916)
* set empty filePath to undefined instead of empty string
([#2836](#2836))
([adfc1ff](adfc1ff)),
closes
[#2825](#2825)
* surface WebMCP tool exceptions in execute_webmcp_tool
([#3107](#3107))
([d80d22e](d80d22e)),
closes
[#2975](#2975)
* url pattern partial ipv4
([#2859](#2859))
([c87d190](c87d190))


### 📄 Documentation

* clarify Antigravity MCP setup for VS Code extension
([#2855](#2855))
([12e13ca](12e13ca))
* clarify scope of --no-javascript-evaluation
([#3100](#3100))
([0c67cd5](0c67cd5))
* correct link to configuration
([#3086](#3086))
([bbb1e36](bbb1e36))
* document trusted host environment in SECURITY.md
([#3125](#3125))
([1352207](1352207))
* fix inaccurate examples in skills and CLI docs
([#2922](#2922))
([ec372b0](ec372b0)),
closes
[#2906](#2906)
[#2907](#2907)
[#2908](#2908)
[#2910](#2910)
[#2912](#2912)
[#2913](#2913)
[#2918](#2918)
[#2919](#2919)
[#2920](#2920)
[#2921](#2921)
* fix some reported issues
([#3099](#3099))
([d5d2f08](d5d2f08))
* include serviceWorkerId parameter for evaluate_script
([#3015](#3015))
([#3129](#3129))
([0623434](0623434))
* mention heapsnapshot being cached between runs
([#3045](#3045))
([f08dbe1](f08dbe1)),
closes
[#2976](#2976)
* **skills:** remove invalid outputDir flag from lighthouse_audit calls
([#3013](#3013))
([#3130](#3130))
([7754226](7754226))
* update documentation and SKILL for get_css_styles tool
([#2824](#2824))
([3c12a91](3c12a91))


### ⚡ Performance

* **cli:** re-use MCPServer.from helpers for daemon
([#2804](#2804))
([89eb3d5](89eb3d5))
* Load heap snapshots in parallel in compare_heapsnapshots
([#3023](#3023))
([20c1391](20c1391))


### 🏗️ Refactor

* centralize config defaults and conflict checks
([#2753](#2753))
([a739ba8](a739ba8))
* create all tools and register per slim mode
([#2874](#2874))
([99847a7](99847a7))
* enable categories by default
([#2811](#2811))
([e33ee48](e33ee48))
* extract CLI examples and conflict list in mcp-options
([#2848](#2848))
([45000d9](45000d9))
* extract config parsing logic in a class
([#2861](#2861))
([e4168d0](e4168d0))
* extract worker logic into McpWorker
([#2800](#2800))
([77165c6](77165c6))
* group Puppeteer and tool options
([#2875](#2875))
([699c4d5](699c4d5))
* lazily initialize McpPage from Target and enumerate targets in
McpContext
([#2812](#2812))
([545cbe3](545cbe3))
* use default Error for toolSchema
([#2822](#2822))
([8b2768d](8b2768d))

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please). See
[documentation](https://github.com/googleapis/release-please#release-please).

Co-authored-by: Alex Rudenko <OrKoN@users.noreply.github.com>
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