Support MCP servers with partial capabilities in vmcp #2416
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Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #2416 +/- ##
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- Coverage 54.58% 54.53% -0.05%
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Files 265 265
Lines 25599 25633 +34
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+ Hits 13972 13979 +7
- Misses 10306 10329 +23
- Partials 1321 1325 +4 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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This is not particularly efficient. We'd need to implement #2417 first. |
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The vmcp was rejecting backends that don't implement all three MCP capabilities (tools, resources, prompts). This violated the MCP specification, which explicitly makes all capabilities optional. The oci-registry MCP server only implements tools, causing vmcp to fail during aggregation when it tried to unconditionally query resources and prompts. Changes: - Query server capabilities during MCP initialization handshake - Conditionally query only advertised capabilities - Return empty results for unsupported capabilities - Add tests for backends with partial capability support This allows vmcp to successfully aggregate backends that implement any subset of tools, resources, and prompts, as intended by the MCP specification. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
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Summary
Fix vmcp to support MCP servers that implement only a subset of capabilities (tools, resources, prompts), per the MCP specification.
Previously, vmcp unconditionally queried all three capabilities from every backend, causing it to reject backends like oci-registry that only implement tools.
Changes
ServerCapabilitiesduring MCP initialization handshakeImpact
Test Results
🤖 Generated with Claude Code