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Merged
e111077 merged 1 commit into from
Aug 21, 2025
Merged

feat(cli/mcp): an initial implementation of a lit mcp server package #4990

e111077 merged 1 commit into from
Aug 21, 2025

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@e111077 e111077 commented May 17, 2025 •
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This implements a very basic mcp server that hooks into our algolia search for lit.dev. The key exposed is a rate-limited read-only key.

Features in this pr:

  • Implements an mcp server
    • Tools can have environment compatibilities
      • local can only run when it has source code in front of it or on a local machine
        • e.g. a tool that runs lit analyzer on your code
      • server can only run when it's on a server
        • e.g. a tool potentially set up at an endpoint on something like lit.dev/mcp that might require special API keys etc
      • any can run in any environment
        • e.g. a tool that can run on either local or server like algolia search
    • Only has an algolia search tool right now. Would be cool to eventually search discord
  • Implements the lit labs mcp command
    • Adds this as a labs command on the lit CLI
    • Implement the --skip-permissions command so that AI tools don't get stuck on the cli asking to install the mcp server
Parent Children
#4970

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github-actions bot commented May 17, 2025 •
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📊 Tachometer Benchmark Results

Summary

nop-update

  • this-change, tip-of-tree, previous-release: unsure 🔍 -4% - +7% (-0.46ms - +0.76ms)
    this-change vs tip-of-tree

render

  • this-change: 42.64ms - 54.27ms
  • this-change, tip-of-tree, previous-release: unsure 🔍 -3% - +5% (-0.67ms - +0.93ms)
    this-change vs tip-of-tree
  • this-change, tip-of-tree, previous-release: unsure 🔍 -1% - +3% (-0.34ms - +1.14ms)
    this-change vs tip-of-tree
  • this-change, tip-of-tree, previous-release: unsure 🔍 -20% - +36% (-8.36ms - +15.52ms)
    this-change vs tip-of-tree

update

  • this-change: 465.62ms - 474.21ms
  • this-change, tip-of-tree, previous-release: unsure 🔍 -3% - +9% (-1.10ms - +3.22ms)
    this-change vs tip-of-tree
  • this-change, tip-of-tree, previous-release: unsure 🔍 -0% - +6% (+0.02ms - +4.07ms)
    this-change vs tip-of-tree
  • this-change, tip-of-tree, previous-release: unsure 🔍 -1% - +1% (-6.94ms - +4.55ms)
    this-change vs tip-of-tree

update-reflect

  • this-change: 457.20ms - 464.49ms
  • this-change, tip-of-tree, previous-release: unsure 🔍 -2% - +1% (-8.43ms - +4.67ms)
    this-change vs tip-of-tree

Results

this-change

render

VersionAvg timevs
42.64ms - 54.27ms-

update

VersionAvg timevs
465.62ms - 474.21ms-

update-reflect

VersionAvg timevs
457.20ms - 464.49ms-
this-change, tip-of-tree, previous-release

render

VersionAvg timevs this-change
vs tip-of-tree
tip-of-tree		vs previous-release
previous-release
this-change
19.16ms - 20.19ms-unsure 🔍
-3% - +5%
-0.67ms - +0.93ms		unsure 🔍
-3% - +4%
-0.63ms - +0.87ms
tip-of-tree
tip-of-tree		18.94ms - 20.15msunsure 🔍
-5% - +3%
-0.93ms - +0.67ms		-unsure 🔍
-4% - +4%
-0.82ms - +0.80ms
previous-release
previous-release		19.02ms - 20.10msunsure 🔍
-4% - +3%
-0.87ms - +0.63ms		unsure 🔍
-4% - +4%
-0.80ms - +0.82ms		-

update

VersionAvg timevs this-change
vs tip-of-tree
tip-of-tree		vs previous-release
previous-release
this-change
35.48ms - 38.16ms-unsure 🔍
-3% - +9%
-1.10ms - +3.22ms		unsure 🔍
-5% - +7%
-1.72ms - +2.46ms
tip-of-tree
tip-of-tree		34.07ms - 37.45msunsure 🔍
-9% - +3%
-3.22ms - +1.10ms		-unsure 🔍
-8% - +4%
-3.02ms - +1.64ms
previous-release
previous-release		34.85ms - 38.06msunsure 🔍
-7% - +5%
-2.46ms - +1.72ms		unsure 🔍
-5% - +9%
-1.64ms - +3.02ms		-

nop-update

VersionAvg timevs this-change
vs tip-of-tree
tip-of-tree		vs previous-release
previous-release
this-change
11.03ms - 11.96ms-unsure 🔍
-4% - +7%
-0.46ms - +0.76ms		unsure 🔍
-5% - +6%
-0.59ms - +0.70ms
tip-of-tree
tip-of-tree		10.95ms - 11.74msunsure 🔍
-7% - +4%
-0.76ms - +0.46ms		-unsure 🔍
-6% - +4%
-0.69ms - +0.50ms
previous-release
previous-release		10.99ms - 11.89msunsure 🔍
-6% - +5%
-0.70ms - +0.59ms		unsure 🔍
-4% - +6%
-0.50ms - +0.69ms		-
this-change, tip-of-tree, previous-release

render

VersionAvg timevs this-change
vs tip-of-tree
tip-of-tree		vs previous-release
previous-release
this-change
35.36ms - 36.41ms-unsure 🔍
-1% - +3%
-0.34ms - +1.14ms		unsure 🔍
-1% - +4%
-0.18ms - +1.25ms
tip-of-tree
tip-of-tree		34.96ms - 36.00msunsure 🔍
-3% - +1%
-1.14ms - +0.34ms		-unsure 🔍
-2% - +2%
-0.59ms - +0.85ms
previous-release
previous-release		34.86ms - 35.84msunsure 🔍
-3% - +0%
-1.25ms - +0.18ms		unsure 🔍
-2% - +2%
-0.85ms - +0.59ms		-

update

VersionAvg timevs this-change
vs tip-of-tree
tip-of-tree		vs previous-release
previous-release
this-change
72.68ms - 75.80ms-unsure 🔍
-0% - +6%
+0.02ms - +4.07ms		unsure 🔍
-2% - +4%
-1.15ms - +2.81ms
tip-of-tree
tip-of-tree		70.90ms - 73.49msfaster ✔
0% - 5%
0.02ms - 4.07ms		-unsure 🔍
-4% - +1%
-3.00ms - +0.57ms
previous-release
previous-release		72.18ms - 74.63msunsure 🔍
-4% - +2%
-2.81ms - +1.15ms		unsure 🔍
-1% - +4%
-0.57ms - +3.00ms		-
this-change, tip-of-tree, previous-release

render

VersionAvg timevs this-change
vs tip-of-tree
tip-of-tree		vs previous-release
previous-release
this-change
38.68ms - 56.50ms-unsure 🔍
-20% - +36%
-8.36ms - +15.52ms		unsure 🔍
-34% - +12%
-19.02ms - +7.40ms
tip-of-tree
tip-of-tree		36.06ms - 51.96msunsure 🔍
-32% - +17%
-15.52ms - +8.36ms		-unsure 🔍
-39% - +4%
-21.97ms - +3.19ms
previous-release
previous-release		43.65ms - 63.15msunsure 🔍
-17% - +42%
-7.40ms - +19.02ms		unsure 🔍
-10% - +52%
-3.19ms - +21.97ms		-

update

VersionAvg timevs this-change
vs tip-of-tree
tip-of-tree		vs previous-release
previous-release
this-change
486.57ms - 494.92ms-unsure 🔍
-1% - +1%
-6.94ms - +4.55ms		unsure 🔍
-1% - +1%
-6.43ms - +5.02ms
tip-of-tree
tip-of-tree		487.99ms - 495.88msunsure 🔍
-1% - +1%
-4.55ms - +6.94ms		-unsure 🔍
-1% - +1%
-5.07ms - +6.05ms
previous-release
previous-release		487.53ms - 495.36msunsure 🔍
-1% - +1%
-5.02ms - +6.43ms		unsure 🔍
-1% - +1%
-6.05ms - +5.07ms		-

update-reflect

VersionAvg timevs this-change
vs tip-of-tree
tip-of-tree		vs previous-release
previous-release
this-change
489.58ms - 498.96ms-unsure 🔍
-2% - +1%
-8.43ms - +4.67ms		unsure 🔍
-2% - +0%
-9.48ms - +2.09ms
tip-of-tree
tip-of-tree		491.59ms - 500.72msunsure 🔍
-1% - +2%
-4.67ms - +8.43ms		-unsure 🔍
-2% - +1%
-7.50ms - +3.87ms
previous-release
previous-release		494.59ms - 501.35msunsure 🔍
-0% - +2%
-2.09ms - +9.48ms		unsure 🔍
-1% - +2%
-3.87ms - +7.50ms		-

tachometer-reporter-action v2 for Benchmarks

@e111077 e111077 mentioned this pull request May 17, 2025
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@e111077 e111077 force-pushed the copilot-instructions branch from 256df49 to ef0d45c Compare May 17, 2025 02:03
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🦋 Changeset detected

Latest commit: 8c71d96

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages
Name Type
@lit-labs/cli-mcp-server Minor
@lit-labs/cli Minor

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@e111077 e111077 force-pushed the copilot-instructions branch from ef0d45c to 2213cb5 Compare May 17, 2025 02:04
@e111077 e111077 marked this pull request as ready for review May 17, 2025 02:05
@e111077 e111077 requested a review from kevinpschaaf as a code owner May 17, 2025 02:05
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e111077 commented May 17, 2025

I had issues writing tests for this. The CLI version of this package seems to be the only way we can test this with with CI. Issues are:

  1. Do we want to include network requests in our tests?
  2. Invoking it from within the directory with npx ran into version conflicts with a transitive commander dependency:
  • npx @modelcontextprotocol/inspector --cli --help # program.name(...).allowExcessArguments is not a function

@e111077 e111077 force-pushed the copilot-instructions branch from 2213cb5 to a81b2a8 Compare May 17, 2025 02:54
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github-actions bot commented May 17, 2025

The size of lit-html.js and lit-core.min.js are as expected.

@e111077 e111077 force-pushed the copilot-instructions branch from a81b2a8 to 42f84b1 Compare May 17, 2025 02:59
@e111077 e111077 force-pushed the copilot-instructions branch from 42f84b1 to 83e7f0b Compare May 17, 2025 04:13
Base automatically changed from copilot-instructions to main May 19, 2025 06:09
@e111077 e111077 requested a review from justinfagnani May 19, 2025 06:10
rictic
rictic reviewed Jun 5, 2025
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Nice!

@e111077 e111077 changed the title [mcp-server] an initial implementation of a lit mcp server package feat(mcp): an initial implementation of a lit mcp server package Jun 5, 2025
@e111077 e111077 force-pushed the mcp-server branch 3 times, most recently from fd29310 to a312af9 Compare June 5, 2025 22:40
@e111077 e111077 changed the title feat(mcp): an initial implementation of a lit mcp server package feat(clit/mcp): an initial implementation of a lit mcp server package Jun 5, 2025
@e111077 e111077 requested a review from rictic June 5, 2025 22:46
@e111077 e111077 force-pushed the mcp-server branch 2 times, most recently from 4353115 to eadf6f8 Compare June 5, 2025 22:50
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e111077 commented Jun 5, 2025

@rictic PTAL: I've made some changes by adding this to the Lit CLI. I've updated the PR description

rictic
rictic reviewed Jun 18, 2025
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packages/labs/cli-mcp-server/src/index.ts
'The environment to run in, either "local" or "server". Server mode will ' +
'only expose MCP commands that are available on the server which are commands that do ' +
'not require local file access.',
typeLabel: '"local", "server"',
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@rictic rictic Jun 18, 2025

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What local filesystem tools are you thinking of?

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@e111077 e111077 Jun 18, 2025

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This is what we were discussing previously:

  • Local, requires filesysten access like generating / finding CE manifests
  • Server, only requires network access to enable a RAG via MCP over HTTP (such as site search)

@e111077 e111077 changed the title feat(clit/mcp): an initial implementation of a lit mcp server package feat(cli/mcp): an initial implementation of a lit mcp server package Jun 19, 2025
@e111077 e111077 force-pushed the mcp-server branch 3 times, most recently from a5ef0ac to ca405be Compare August 21, 2025 18:48
@e111077
[mcp-server] an initial implementation of a lit mcp server package
8c71d96 
This implements a very basic mcp server that hooks into our algolia search for lit.dev. The key exposed is a rate-limited read-only key.
@e111077 e111077 enabled auto-merge (rebase) August 21, 2025 22:28
@e111077 e111077 merged commit 36c6c00 into main Aug 21, 2025
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@e111077 e111077 deleted the mcp-server branch August 21, 2025 22:32
@lit-robot lit-robot mentioned this pull request Dec 18, 2025
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@rictic rictic rictic approved these changes

@kevinpschaaf kevinpschaaf Awaiting requested review from kevinpschaaf kevinpschaaf is a code owner

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