The method ```io.modelcontextprotocol.client.McpAsyncClient#listTools()``` never returns if the ```result.nextCursor()``` is an empty string instead of a null · Issue #575 · modelcontextprotocol/java-sdk · GitHub

modelcontextprotocol / java-sdk Public

• Notifications You must be signed in to change notification settings
• Fork 1.1k
• Star 3.7k

• Code
• Issues 133
• Pull requests 162
• Discussions
• Actions
• Projects
• Security and quality 4
• Insights

Additional navigation options

The method io.modelcontextprotocol.client.McpAsyncClient#listTools() never returns if the result.nextCursor() is an empty string instead of a null #575

Copy link

Copy link

Closed

Bug

#954

Closed

The method io.modelcontextprotocol.client.McpAsyncClient#listTools() never returns if the result.nextCursor() is an empty string instead of a null#575

Bug

#954

Copy link

Labels

P3Nice to haves, rare edge casesNice to haves, rare edge casesbugSomething isn't workingSomething isn't working

Description

jthann

opened on Sep 25, 2025

Issue body actions

I've found in some MCP server implementations the nextCursor in response is empty string instead of null, leading to dead loop in the method of following reference.

java-sdk/mcp-core/src/main/java/io/modelcontextprotocol/client/McpAsyncClient.java

Line 557 in 7f16cd0

.expand(result -> (result.nextCursor() != null) ? this.listTools(result.nextCursor()) : Mono.empty())

Reactions are currently unavailable

Metadata

Metadata

Assignees

No one assigned

Labels

P3Nice to haves, rare edge casesNice to haves, rare edge casesbugSomething isn't workingSomething isn't working

Type

Bug

Projects

No projects

Milestone

No milestone

Relationships

None yet

Development

No branches or pull requests

Issue actions