René's URL Explorer Experiment


Title: Don't block the event loop on non-async functions by Kludex · Pull Request #1909 · modelcontextprotocol/python-sdk · GitHub

Open Graph Title: Don't block the event loop on non-async functions by Kludex · Pull Request #1909 · modelcontextprotocol/python-sdk

X Title: Don't block the event loop on non-async functions by Kludex · Pull Request #1909 · modelcontextprotocol/python-sdk

Description: The official Python SDK for Model Context Protocol servers and clients - Don't block the event loop on non-async functions by Kludex · Pull Request #1909 · modelcontextprotocol/python-sdk

Open Graph Description: Closes fastmcp tool func block asyncio #1839

X Description: Closes fastmcp tool func block asyncio #1839

Opengraph URL: https://github.com/modelcontextprotocol/python-sdk/pull/1909

X: @github

direct link

Domain: github.com

route-pattern/_view_fragments/voltron/pull_requests/show/:user_id/:repository/:id/pull_request_layout(.:format)
route-controllervoltron_pull_requests_fragments
route-actionpull_request_layout
fetch-noncev2:deaca2ca-27a6-7813-1aed-7450cc3345b0
current-catalog-service-hashae870bc5e265a340912cde392f23dad3671a0a881730ffdadd82f2f57d81641b
request-idB66A:1F7BBA:CD3E30:117423A:6A593ACD
html-safe-noncecc5eadca6d1462a1a9e6579217d515b7405eea09f5071e01fd2d7f302277efd7
visitor-payloadeyJyZWZlcnJlciI6IiIsInJlcXVlc3RfaWQiOiJCNjZBOjFGN0JCQTpDRDNFMzA6MTE3NDIzQTo2QTU5M0FDRCIsInZpc2l0b3JfaWQiOiI1MzgxMTgxMjkzMzczMTgwOTQiLCJyZWdpb25fZWRnZSI6ImlhZCIsInJlZ2lvbl9yZW5kZXIiOiJpYWQifQ==
visitor-hmac2ce41ac4750e37a38d27d59f5c06ad30721f5e1289a710b5a08cb5383d54ca92
hovercard-subject-tagpull_request:3185794143
github-keyboard-shortcutsrepository,pull-request-list,pull-request-conversation,pull-request-files-changed,copilot
google-site-verificationApib7-x98H0j5cPqHWwSMm6dNU4GmODRoqxLiDzdx9I
octolytics-urlhttps://collector.github.com/github/collect
analytics-location///voltron/pull_requests_fragments/pull_request_layout
fb:app_id1401488693436528
apple-itunes-appapp-id=1477376905, app-argument=https://github.com/_view_fragments/voltron/pull_requests/show/modelcontextprotocol/python-sdk/1909/pull_request_layout
twitter:imagehttps://opengraph.githubassets.com/50c8dc064fa31f436b581c7db095141b2de87e106b3bf1b3adc25230b407d59a/modelcontextprotocol/python-sdk/pull/1909
twitter:cardsummary_large_image
og:imagehttps://opengraph.githubassets.com/50c8dc064fa31f436b581c7db095141b2de87e106b3bf1b3adc25230b407d59a/modelcontextprotocol/python-sdk/pull/1909
og:image:altCloses fastmcp tool func block asyncio #1839
og:image:width1200
og:image:height600
og:site_nameGitHub
og:typeobject
og:author:usernameKludex
hostnamegithub.com
expected-hostnamegithub.com
None1b31c9453e1607b2781513084b4770f67217e549834c85b76960d7b13626f7c8
turbo-cache-controlno-cache
go-importgithub.com/modelcontextprotocol/python-sdk git https://github.com/modelcontextprotocol/python-sdk.git
octolytics-dimension-user_id182288589
octolytics-dimension-user_loginmodelcontextprotocol
octolytics-dimension-repository_id862584018
octolytics-dimension-repository_nwomodelcontextprotocol/python-sdk
octolytics-dimension-repository_publictrue
octolytics-dimension-repository_is_forkfalse
octolytics-dimension-repository_network_root_id862584018
octolytics-dimension-repository_network_root_nwomodelcontextprotocol/python-sdk
turbo-body-classeslogged-out env-production page-responsive
disable-turbofalse
browser-stats-urlhttps://api.github.com/_private/browser/stats
browser-errors-urlhttps://api.github.com/_private/browser/errors
release220f27779da5b92b5e17fcaef93e474cc8affba3
ui-targetfull
theme-color#1e2327
color-schemelight dark

Links:

Skip to contenthttps://github.com/modelcontextprotocol/python-sdk/pull/1909#start-of-content
https://github.com/
Sign in https://github.com/login?return_to=https%3A%2F%2Fgithub.com%2Fmodelcontextprotocol%2Fpython-sdk%2Fpull%2F1909
GitHub CopilotWrite better code with AIhttps://github.com/features/copilot
GitHub Copilot appDirect agents from issue to mergehttps://github.com/features/ai/github-app
MCP RegistryNewIntegrate external toolshttps://github.com/mcp
ActionsAutomate any workflowhttps://github.com/features/actions
CodespacesInstant dev environmentshttps://github.com/features/codespaces
IssuesPlan and track workhttps://github.com/features/issues
Code ReviewManage code changeshttps://github.com/features/code-review
GitHub Advanced SecurityFind and fix vulnerabilitieshttps://github.com/security/advanced-security
Code securitySecure your code as you buildhttps://github.com/security/advanced-security/code-security
Secret protectionStop leaks before they starthttps://github.com/security/advanced-security/secret-protection
Why GitHubhttps://github.com/why-github
Documentationhttps://docs.github.com
Bloghttps://github.blog
Changeloghttps://github.blog/changelog
Marketplacehttps://github.com/marketplace
View all featureshttps://github.com/features
Enterpriseshttps://github.com/enterprise
Small and medium teamshttps://github.com/team
Startupshttps://github.com/enterprise/startups
Nonprofitshttps://github.com/solutions/industry/nonprofits
App Modernizationhttps://github.com/solutions/use-case/app-modernization
DevSecOpshttps://github.com/solutions/use-case/devsecops
DevOpshttps://github.com/solutions/use-case/devops
CI/CDhttps://github.com/solutions/use-case/ci-cd
View all use caseshttps://github.com/solutions/use-case
Healthcarehttps://github.com/solutions/industry/healthcare
Financial serviceshttps://github.com/solutions/industry/financial-services
Manufacturinghttps://github.com/solutions/industry/manufacturing
Governmenthttps://github.com/solutions/industry/government
View all industrieshttps://github.com/solutions/industry
View all solutionshttps://github.com/solutions
AIhttps://github.com/resources/articles?topic=ai
Software Developmenthttps://github.com/resources/articles?topic=software-development
DevOpshttps://github.com/resources/articles?topic=devops
Securityhttps://github.com/resources/articles?topic=security
View all topicshttps://github.com/resources/articles
Customer storieshttps://github.com/customer-stories
Events & webinarshttps://github.com/resources/events
Ebooks & reportshttps://github.com/resources/whitepapers
Business insightshttps://github.com/solutions/executive-insights
GitHub Skillshttps://skills.github.com
Documentationhttps://docs.github.com
Customer supporthttps://support.github.com
Community forumhttps://github.com/orgs/community/discussions
Trust centerhttps://github.com/trust-center
Partnershttps://github.com/partners
View all resourceshttps://github.com/resources
GitHub SponsorsFund open source developershttps://github.com/open-source/sponsors
Security Labhttps://securitylab.github.com
Maintainer Communityhttps://maintainers.github.com
Acceleratorhttps://github.com/open-source/accelerator
GitHub Starshttps://stars.github.com
Archive Programhttps://archiveprogram.github.com
Topicshttps://github.com/topics
Trendinghttps://github.com/trending
Collectionshttps://github.com/collections
Enterprise platformAI-powered developer platformhttps://github.com/enterprise
GitHub Advanced SecurityEnterprise-grade security featureshttps://github.com/security/advanced-security
Copilot for BusinessEnterprise-grade AI featureshttps://github.com/features/copilot/copilot-business
Premium SupportEnterprise-grade 24/7 supporthttps://github.com/enterprise/premium-support
Pricinghttps://github.com/pricing
Search syntax tipshttps://docs.github.com/search-github/github-code-search/understanding-github-code-search-syntax
documentationhttps://docs.github.com/search-github/github-code-search/understanding-github-code-search-syntax
Sign in https://github.com/login?return_to=https%3A%2F%2Fgithub.com%2Fmodelcontextprotocol%2Fpython-sdk%2Fpull%2F1909
Sign up https://github.com/signup?ref_cta=Sign+up&ref_loc=header+logged+out&ref_page=%2F%3Cuser-name%3E%2F%3Crepo-name%3E%2Fvoltron%2Fpull_requests_fragments%2Fpull_request_layout&source=header-repo&source_repo=modelcontextprotocol%2Fpython-sdk
Reloadhttps://github.com/modelcontextprotocol/python-sdk/pull/1909
Reloadhttps://github.com/modelcontextprotocol/python-sdk/pull/1909
Reloadhttps://github.com/modelcontextprotocol/python-sdk/pull/1909
Please reload this pagehttps://github.com/modelcontextprotocol/python-sdk/pull/1909
modelcontextprotocol https://github.com/modelcontextprotocol
python-sdkhttps://github.com/modelcontextprotocol/python-sdk
Notifications https://github.com/login?return_to=%2Fmodelcontextprotocol%2Fpython-sdk
Fork 3.7k https://github.com/login?return_to=%2Fmodelcontextprotocol%2Fpython-sdk
Star 23.6k https://github.com/login?return_to=%2Fmodelcontextprotocol%2Fpython-sdk
Code https://github.com/modelcontextprotocol/python-sdk
Issues 255 https://github.com/modelcontextprotocol/python-sdk/issues
Pull requests 301 https://github.com/modelcontextprotocol/python-sdk/pulls
Actions https://github.com/modelcontextprotocol/python-sdk/actions
Projects https://github.com/modelcontextprotocol/python-sdk/projects
Models https://github.com/modelcontextprotocol/python-sdk/models
Security and quality 6 https://github.com/modelcontextprotocol/python-sdk/security
Insights https://github.com/modelcontextprotocol/python-sdk/pulse
Code https://github.com/modelcontextprotocol/python-sdk
Issues https://github.com/modelcontextprotocol/python-sdk/issues
Pull requests https://github.com/modelcontextprotocol/python-sdk/pulls
Actions https://github.com/modelcontextprotocol/python-sdk/actions
Projects https://github.com/modelcontextprotocol/python-sdk/projects
Models https://github.com/modelcontextprotocol/python-sdk/models
Security and quality https://github.com/modelcontextprotocol/python-sdk/security
Insights https://github.com/modelcontextprotocol/python-sdk/pulse
Kludexhttps://github.com/Kludex
mainhttps://github.com/modelcontextprotocol/python-sdk/tree/main
run-anyio-to-threadhttps://github.com/modelcontextprotocol/python-sdk/tree/run-anyio-to-thread
Conversationhttps://github.com/modelcontextprotocol/python-sdk/pull/1909
Commits2 (2)https://github.com/modelcontextprotocol/python-sdk/pull/1909/commits
Checkshttps://github.com/modelcontextprotocol/python-sdk/pull/1909/checks
Files changedhttps://github.com/modelcontextprotocol/python-sdk/pull/1909/files
Don't block the event loop on non-async functionshttps://github.com/modelcontextprotocol/python-sdk/pull/1909#top
Kludexhttps://github.com/Kludex
mainhttps://github.com/modelcontextprotocol/python-sdk/tree/main
run-anyio-to-threadhttps://github.com/modelcontextprotocol/python-sdk/tree/run-anyio-to-thread
https://github.com/Kludex
Kludexhttps://github.com/Kludex
Jan 18, 2026https://github.com/modelcontextprotocol/python-sdk/pull/1909#issue-3827363222
Please reload this pagehttps://github.com/modelcontextprotocol/python-sdk/pull/1909
fastmcp tool func block asyncio #1839https://github.com/modelcontextprotocol/python-sdk/issues/1839
Please reload this pagehttps://github.com/modelcontextprotocol/python-sdk/pull/1909
https://github.com/Kludex
Don't block the event loop on non-async functionshttps://github.com/modelcontextprotocol/python-sdk/pull/1909/commits/c4830552c29191f13fc399c90a605f7766b0c688
c483055https://github.com/modelcontextprotocol/python-sdk/pull/1909/commits/c4830552c29191f13fc399c90a605f7766b0c688
https://github.com/Kludex
Kludexhttps://github.com/Kludex
felixweinbergerhttps://github.com/felixweinberger
maxisbeyhttps://github.com/maxisbey
January 18, 2026 21:39https://github.com/modelcontextprotocol/python-sdk/pull/1909#event-22124800099
https://github.com/maxisbey
maxisbeyhttps://github.com/maxisbey
Jan 19, 2026 https://github.com/modelcontextprotocol/python-sdk/pull/1909#pullrequestreview-3678105967
View reviewed changes https://github.com/modelcontextprotocol/python-sdk/pull/1909/files/c4830552c29191f13fc399c90a605f7766b0c688
https://github.com/Kludex
Merge branch 'main' into run-anyio-to-threadhttps://github.com/modelcontextprotocol/python-sdk/pull/1909/commits/52e92bf8645e2f8723267eab66efe6b79047ecd0
52e92bfhttps://github.com/modelcontextprotocol/python-sdk/pull/1909/commits/52e92bf8645e2f8723267eab66efe6b79047ecd0
https://github.com/Kludex
Kludexhttps://github.com/Kludex
maxisbeyhttps://github.com/maxisbey
stale reviewhttps://github.com/modelcontextprotocol/python-sdk/pull/1909#pullrequestreview-3678105967
52e92bfhttps://github.com/modelcontextprotocol/python-sdk/commit/52e92bf8645e2f8723267eab66efe6b79047ecd0
January 19, 2026 13:29https://github.com/modelcontextprotocol/python-sdk/pull/1909#event-22138562584
https://github.com/maxisbey
maxisbeyhttps://github.com/maxisbey
Jan 19, 2026 https://github.com/modelcontextprotocol/python-sdk/pull/1909#pullrequestreview-3678172327
View reviewed changes https://github.com/modelcontextprotocol/python-sdk/pull/1909/files/52e92bf8645e2f8723267eab66efe6b79047ecd0
https://github.com/Kludex
Kludexhttps://github.com/Kludex
1c258aehttps://github.com/modelcontextprotocol/python-sdk/commit/1c258ae203147d21f74c369ef2aed44563009322
Jan 19, 2026https://github.com/modelcontextprotocol/python-sdk/pull/1909#event-22138960430
Please reload this pagehttps://github.com/modelcontextprotocol/python-sdk/pull/1909
https://github.com/Kludex
Kludexhttps://github.com/Kludex
January 19, 2026 13:47https://github.com/modelcontextprotocol/python-sdk/pull/1909#event-22138961586
maxisbeyhttps://github.com/maxisbey
Mar 31, 2026 https://github.com/modelcontextprotocol/python-sdk/pull/1909#ref-commit-904dc9f
https://github.com/maxisbey
Don't block the event loop on sync resource and prompt functionshttps://github.com/modelcontextprotocol/python-sdk/commit/904dc9fc6bbbe6cb06246734009c83549669554d
904dc9fhttps://github.com/modelcontextprotocol/python-sdk/commit/904dc9fc6bbbe6cb06246734009c83549669554d
#1909https://github.com/modelcontextprotocol/python-sdk/pull/1909
#1646https://github.com/modelcontextprotocol/python-sdk/issues/1646
https://github.com/maxisbey
maxisbeyhttps://github.com/maxisbey
Mar 31, 2026 https://github.com/modelcontextprotocol/python-sdk/pull/1909#ref-pullrequest-4180930581
Don't block the event loop on sync resource and prompt functions #2380 https://github.com/modelcontextprotocol/python-sdk/pull/2380
https://github.com/maxisbey
maxisbeyhttps://github.com/maxisbey
May 18, 2026 https://github.com/modelcontextprotocol/python-sdk/pull/1909#ref-issue-3646239394
Why synchronous @mcp.tool definition is not supported for parallelism? #1646 https://github.com/modelcontextprotocol/python-sdk/issues/1646
https://github.com/scotthibbs
scotthibbshttps://github.com/scotthibbs
Jul 12, 2026 https://github.com/modelcontextprotocol/python-sdk/pull/1909#ref-issue-4868174044
Heavy sync init work (e.g. local ML models) starves stdio initialize/tool calls even with threadpool offload -- Windows GIL contention #3089 https://github.com/modelcontextprotocol/python-sdk/issues/3089
https://github.co/hiddenchars
https://github.com/modelcontextprotocol/python-sdk/pull/{{ revealButtonHref }}
Sign up for freehttps://github.com/join?source=comment-repo
Sign in to commenthttps://github.com/login?return_to=https%3A%2F%2Fgithub.com%2Fmodelcontextprotocol%2Fpython-sdk%2Fpull%2F1909
https://github.com/maxisbey
maxisbey https://github.com/maxisbey
https://github.com/modelcontextprotocol/python-sdk/pull/1909/files/52e92bf8645e2f8723267eab66efe6b79047ecd0
https://github.com/felixweinberger
felixweinberger https://github.com/felixweinberger
fastmcp tool func block asyncio https://github.com/modelcontextprotocol/python-sdk/issues/1839
Please reload this pagehttps://github.com/modelcontextprotocol/python-sdk/pull/1909
https://github.com/Kludex
https://github.com/maxisbey
https://github.com
Termshttps://docs.github.com/site-policy/github-terms/github-terms-of-service
Privacyhttps://docs.github.com/site-policy/privacy-policies/github-privacy-statement
Securityhttps://github.com/security
Statushttps://www.githubstatus.com/
Communityhttps://github.community/
Docshttps://docs.github.com/
Contacthttps://support.github.com?tags=dotcom-footer

Viewport: width=device-width

URLs of crawlers that visited me.