modelcontextprotocol/csharp-sdk

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The official C# SDK for Model Context Protocol servers and clients. Maintained in collaboration with Microsoft.

Stars: 4.5k
Forks: 814
Open beginner issues: 1
Indexed issues: 126
Avg merge: 9d 19h
Merged PRs (30d): 4

Dominant language: C#
License: No license data
Last GitHub push: Sep 19, 2026
Latest indexed: Sep 20, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: help wanted

Beginner friendly Everything

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126 open issues indexed

Documentation slightly hard to find Open

documentation enhancement P3 ready for work

modelcontextprotocol/csharp-sdk#1493 · 3 comments · 1 reaction · 1 assignee · Opened Apr 2, 2026
Authorization Server & Protected Resource Metadata inspection Open

area-auth enhancement needs confirmation P2

Difficulty 5/5 Over a week Newbie friendliness 38/100

modelcontextprotocol/csharp-sdk#1487 · 1 reaction · Opened Apr 1, 2026
Built-in server-side support for incremental scope consent (SEP-835) Open

area-auth enhancement P3

Difficulty 4/5 3-5 days Newbie friendliness 38/100

modelcontextprotocol/csharp-sdk#1482 · 1 comment · Opened Mar 31, 2026
McpClient.CreateAsync times out behind APIM in .NET SDK while MCP Inspector/Azure AI Foundry succeed Open

bug P2 ready for work

Difficulty 4/5 3-5 days Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#1470 · Opened Mar 27, 2026
Add client-side tool call interceptor (annotation-aware policy enforcement) Open

enhancement P2 ready for work

Difficulty 5/5 Over a week Newbie friendliness 45/100

modelcontextprotocol/csharp-sdk#1453 · 2 comments · Opened Mar 20, 2026
[Auth] OAuth proxy / DCR facade for non-DCR providers (e.g. Entra ID + Claude Code) Open

area-auth enhancement P2 ready for work

Difficulty 5/5 Over a week Newbie friendliness 25/100

modelcontextprotocol/csharp-sdk#1446 · 4 comments · 11 reactions · Opened Mar 18, 2026
Alternative to `RunSessionHandler` for accessing MCP servers Open

blocked enhancement needs confirmation P2

Difficulty 5/5 Over a week Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#1416 · 2 comments · Opened Mar 8, 2026
Export Control Classification Number for these packages? Open

documentation needs confirmation P3 question

Difficulty 1/5 Under an hour Newbie friendliness 25/100

modelcontextprotocol/csharp-sdk#1413 · 1 comment · Opened Mar 6, 2026
Sample: stdio-to-HTTP bridge for AI clients that only support stdio transport Open

documentation enhancement P3 ready for work

Difficulty 3/5 1-2 days Newbie friendliness 68/100

modelcontextprotocol/csharp-sdk#1389 · 1 comment · 1 reaction · Opened Feb 25, 2026
Cancellation support via CancellationToken's fails Open

bug P2 ready for work

Difficulty 4/5 3-5 days Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#1365 · 5 comments · Opened Feb 23, 2026
Custom filters Open

enhancement P3 ready for work

Difficulty 4/5 3-5 days Newbie friendliness 42/100

modelcontextprotocol/csharp-sdk#1314 · 1 reaction · Opened Feb 19, 2026
Add DeleteStreamsForSessionAsync to ISseEventStreamStore Open

enhancement P3 ready for work

Difficulty 3/5 1-2 days Newbie friendliness 58/100

modelcontextprotocol/csharp-sdk#1287 · 2 comments · Opened Feb 16, 2026
notifications/tools/list_changed handler apparently times out over Streamable HTTP Open

bug help wanted P3 ready for work

Difficulty 4/5 3-5 days Newbie friendliness 45/100

modelcontextprotocol/csharp-sdk#1239 · 2 comments · Opened Feb 3, 2026
Version-Based Tool Registration for MCP Server Open

enhancement P3 ready for work

Difficulty 5/5 Over a week Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#1216 · 1 comment · 10 reactions · Opened Jan 30, 2026
Host multiple MCP servers with different HTTP endpoints in one process using keyed services Open

enhancement needs confirmation

Difficulty 5/5 Over a week Newbie friendliness 38/100

modelcontextprotocol/csharp-sdk#1202 · 4 comments · 4 reactions · Opened Jan 29, 2026
Remove use of AsyncLocal to track Task input_required status Open

enhancement P2 ready for work

Difficulty 4/5 3-5 days Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#1185 · 1 comment · Opened Jan 28, 2026
Support elicitation and sampling requests in tasks/result response Open

enhancement P2 ready for work

Difficulty 4/5 3-5 days Newbie friendliness 38/100

modelcontextprotocol/csharp-sdk#1184 · Opened Jan 28, 2026
Support using WithStreamServerTransport for multiple in-process mcp servers Open

enhancement needs confirmation P3

Difficulty 4/5 3-5 days Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#1172 · Opened Jan 22, 2026
Github copilot not setting bearer token on acces to tools. Open

area-auth bug help wanted needs confirmation P3

Difficulty 4/5 3-5 days Newbie friendliness 30/100

modelcontextprotocol/csharp-sdk#1166 · 2 comments · Opened Jan 19, 2026
Allow JsonSerializerOptions without TypeInfoResolver Open

enhancement needs confirmation P3

Difficulty 2/5 1-3 hours Newbie friendliness 52/100

modelcontextprotocol/csharp-sdk#1150 · 2 comments · Opened Jan 15, 2026
Support stream resumption in stateless mode Open

enhancement needs confirmation P3

Difficulty 4/5 3-5 days Newbie friendliness 25/100

modelcontextprotocol/csharp-sdk#1131 · 2 reactions · Opened Jan 7, 2026
Request for Sample: ASP.NET Core MCP Client with One Persisted Connection Per User Session Open

documentation enhancement help wanted P3 ready for work

Difficulty 5/5 Over a week Newbie friendliness 38/100

modelcontextprotocol/csharp-sdk#1126 · 6 comments · Opened Dec 29, 2025
AddSingleton does not work as expected Open

enhancement needs confirmation P3

Difficulty 4/5 3-5 days Newbie friendliness 25/100

modelcontextprotocol/csharp-sdk#1111 · 8 comments · Opened Dec 17, 2025
Robustly parse quoted WWW-Authenticate parameters Open

bug P2

Difficulty 3/5 1-2 days Newbie friendliness 55/100

modelcontextprotocol/csharp-sdk#1088 · Opened Dec 12, 2025
Practical OAuth implementation for production Open

area-auth documentation enhancement help wanted P3 ready for work

Difficulty 5/5 Over a week Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#1052 · 1 comment · Opened Dec 3, 2025
WWW-Authenticate header does not contain a resource metadata params Open

area-auth bug P2

Difficulty 3/5 1-2 days Newbie friendliness 48/100

modelcontextprotocol/csharp-sdk#1050 · 3 comments · 1 reaction · Opened Dec 1, 2025
Authorize with specific JWT scheme and [Authorize(...)] attribute Open

area-auth enhancement P2 ready for work

Difficulty 4/5 3-5 days Newbie friendliness 45/100

modelcontextprotocol/csharp-sdk#968 · 3 comments · 1 reaction · Opened Nov 17, 2025
ToolResult always returns as "Text" with without be decoded Open

enhancement needs confirmation P3

Difficulty 4/5 3-5 days Newbie friendliness 45/100

modelcontextprotocol/csharp-sdk#962 · 14 comments · Opened Nov 13, 2025
Transfer-Encoding=Chunked causes issues with locally run Azure Functions Open

bug needs confirmation P2

Difficulty 4/5 3-5 days Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#932 · 1 comment · Opened Oct 31, 2025
Support externally sourced JWT in Auth header from MCP client Open

area-auth enhancement P2 ready for work

Difficulty 4/5 3-5 days Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#917 · 2 comments · Opened Oct 23, 2025
Expose OAuth metadata, pass token to API without validation Open

area-auth enhancement P2 ready for work

Difficulty 4/5 3-5 days Newbie friendliness 45/100

modelcontextprotocol/csharp-sdk#893 · 6 comments · Opened Oct 17, 2025
Make EverythingServer capable of running either stdio or http Open

area-tests enhancement help wanted P3 ready for work

Difficulty 5/5 Over a week Newbie friendliness 45/100

modelcontextprotocol/csharp-sdk#889 · 3 comments · 2 reactions · Opened Oct 16, 2025
Scopes not forwarded to DCR endpoint and duplication of RedirectUris Open

area-auth bug needs confirmation P2

Difficulty 4/5 3-5 days Newbie friendliness 45/100

modelcontextprotocol/csharp-sdk#887 · Opened Oct 16, 2025
OAuth Flow not working for Atlassian MCP and Github MCP Open

area-auth bug needs confirmation P2

Difficulty 4/5 3-5 days Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#842 · 4 comments · Opened Oct 9, 2025
DLLs are not Code Signed Open

area-infrastructure blocked enhancement needs confirmation P2

Difficulty 4/5 3-5 days Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#833 · 3 comments · Opened Oct 3, 2025
Proposing a Distributed Remote Transport Abstraction Open

enhancement needs confirmation

Difficulty 5/5 Over a week Newbie friendliness 25/100

modelcontextprotocol/csharp-sdk#828 · 2 comments · Opened Oct 2, 2025
Is there a way to run multiple stateful MCP servers? Open

enhancement needs confirmation

Difficulty 5/5 Over a week Newbie friendliness 30/100

modelcontextprotocol/csharp-sdk#814 · 4 comments · 4 reactions · Opened Sep 24, 2025
Allow to specify `JsonSerializerOptions` and `AIJsonSchemaCreateOptions` when adding capabilities to MCP server Open

enhancement needs confirmation

modelcontextprotocol/csharp-sdk#795 · 1 comment · 1 assignee · Opened Sep 19, 2025
Passing a malformed body throws a 500 error instead of 400. Very hard to figure out what is incorrect in the request being issued by the caller Open

bug help wanted needs confirmation P3

Difficulty 3/5 1-2 days Newbie friendliness 55/100

modelcontextprotocol/csharp-sdk#788 · 1 comment · Opened Sep 17, 2025
SEP-1046: Support OAuth client credentials flow in authorization Open

area-auth enhancement P3

modelcontextprotocol/csharp-sdk#772 · 3 comments · 1 assignee · Opened Sep 15, 2025
How do I resolve an instance of `IMcpServer` when using `WithHttpTransport`? Open

needs confirmation question

Difficulty 4/5 3-5 days Newbie friendliness 38/100

modelcontextprotocol/csharp-sdk#768 · 6 comments · Opened Sep 14, 2025
Cache authorization policy lookups for IMcpServerPrimitives Open

enhancement needs confirmation

Difficulty 4/5 3-5 days Newbie friendliness 48/100

modelcontextprotocol/csharp-sdk#762 · 1 comment · Opened Sep 10, 2025
Middleware tools list (different tool set based on user access) Open

enhancement needs confirmation

Difficulty 5/5 Over a week Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#759 · 2 comments · Opened Sep 10, 2025
Dynamic Tool Description based on Route Variable in path Open

enhancement needs confirmation

Difficulty 4/5 3-5 days Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#758 · 1 comment · Opened Sep 10, 2025
SseClientTransportOptions.Endpoint needs a way for a consumer to control if the corresponding Resource ends with a trailing slash or not Open

enhancement needs confirmation

Difficulty 3/5 1-2 days Newbie friendliness 35/100

modelcontextprotocol/csharp-sdk#757 · 2 comments · Opened Sep 8, 2025
How can a server using the SSE (Server-Sent Events) model over HTTP support additional content like images within the conversational context? Open

enhancement needs confirmation

Difficulty 5/5 Over a week Newbie friendliness 25/100

modelcontextprotocol/csharp-sdk#752 · 2 comments · Opened Sep 3, 2025
Add option for automatic server-side keep-alive for SSE responses Open

enhancement needs confirmation

Difficulty 3/5 1-2 days Newbie friendliness 55/100

modelcontextprotocol/csharp-sdk#736 · 3 comments · Opened Aug 27, 2025
Passing ACR_VALUES TO Token Endpoint Open

enhancement needs confirmation

Difficulty 3/5 1-2 days Newbie friendliness 45/100

modelcontextprotocol/csharp-sdk#720 · Opened Aug 20, 2025
Is it possible to make the `StreamableHttpHandler` and `SseHandler` public? Open

enhancement needs confirmation P3

Difficulty 3/5 1-2 days Newbie friendliness 58/100

modelcontextprotocol/csharp-sdk#710 · 4 comments · Opened Aug 15, 2025
ProtectedMcpServer sample doesn't work with VSCode auth flow Open

area-auth bug help wanted needs confirmation P3

Difficulty 4/5 3-5 days Newbie friendliness 48/100

modelcontextprotocol/csharp-sdk#689 · 1 comment · Opened Aug 8, 2025

modelcontextprotocol/csharp-sdk

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