mcp-server-tester does not seem to exit once all tests complete

[alocay]

When I run npx mcp-server-tester tools tool-tests.yaml --server-config server-config.json I see the output:

Running tools tests from: tool-tests.yaml

MCP Server Tester v1.4.0

📋 Tools Tests
✅ Tool discovery: 8/8 expected tools found (...)
✅ Test 1: PASSED
...

📊 Results: 5/5 tests passed (0.1s)

but then it hangs there until I end it via ctrl+c. I'm assuming this is not expected?

[steviec]

Not expected. Can you send me your tool-tests.yaml and server-config.json? I'll see if I can repro.

[alocay]

For this setup the MCP Server run is the Apollo MCP Server 0.7.3 which can be found at https://github.com/apollographql/apollo-mcp-server/releases. I'm using the aarach64 apple darwin release. Can also be grabbed via curl -sSL https://mcp.apollo.dev/download/nix/latest | sh (https://www.apollographql.com/docs/apollo-mcp-server/install). The configuration file used by the mcp server has it configured for stdio transport.

The server-config file (used by the tester) looks like this:

{
    "mcpServers": {
        "mcp-server": {
            "command": "./apollo-mcp-server",
            "args": ["config.yaml"]
        }
    }
}

tools-tests.yaml - https://gist.github.com/alocay/6ba03b691d8413ce9201c9bf52e1cd71
config.yaml file referenced as the argument: https://gist.github.com/alocay/dbc7a86629cd2c50ec81c5040cca7acb
api.yaml file referenced in the config file: https://github.com/apollographql/apollo-mcp-server/blob/main/graphql/TheSpaceDevs/api.graphql
The operations directory: https://github.com/apollographql/apollo-mcp-server/tree/main/graphql/TheSpaceDevs/operations

The directory structure when I ran this:

/tester
    apollo-mcp-server
    config.yaml
    mcp-server-config.json
    operations/
    api.graphql

The command I ran to test:

npx mcp-server-tester tools tool-tests.yaml --server-config mcp-server-config.json

[alocay]

Any chance to look at this? I know it's a bit of a setup, so let me know if I can help in some way.

[steviec]

Really sorry for the slow response, got totally buried. I should have time between now and Friday to fix in off hours.

[steviec]

Fixed. Your repro was great, I was able to see the problem immediately. It was a bug in the official typescript-sdk. There's THREE open PRs to fix it, none are merged, so I just patched it. Should be available in newest ver of the server tester.
modelcontextprotocol/typescript-sdk#314
modelcontextprotocol/typescript-sdk#818
modelcontextprotocol/typescript-sdk#821

[steviec]

(and @alocay, can you confirm it works for you consistently now?

[alocay]

(and @alocay, can you confirm it works for you consistently now?

Hmmm I can't tell if I'm doing something wrong if I run npx mcp-server-tester I get blank output and exits. No matter what options I give (even no options) I just see blank output and exit. Did something change in how it's run in v1.4.1?

Update: I verified that running npx mcp-server-tester@1.4.0 does emit the expected output but not 1.4.1.

[steviec]

Weird, I'll look tonight, thanks for the fast response.

[alocay]

Weird, I'll look tonight, thanks for the fast response.

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