Fix MCP stdio framing and negotiate protocolVersion#120
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Replace LSP-style Content-Length framing with the MCP stdio transport's newline-delimited JSON on both input and output, negotiate the client's protocolVersion during initialize (latest supported: 2025-06-18), and make stdin buffering synchronous with a serial message queue so interleaved chunks cannot drop or duplicate messages. Closes #68 Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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| } from "../runtime/protocol/openphone-runtime-tools.mjs"; | ||
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| const PROTOCOL_VERSION = "2025-11-25"; | ||
| export const SUPPORTED_PROTOCOL_VERSIONS = ["2025-06-18"]; |
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For clients that only advertise the current MCP protocolVersion (2025-11-25), this array makes initialize respond with 2025-06-18, after which such clients should disconnect rather than use the server. The latest MCP lifecycle spec lists 2025-11-25 as the latest version and requires echoing the requested version when the server supports it (https://modelcontextprotocol.io/specification/2025-11-25/basic/lifecycle); since the server was already advertising that version before this change and this patch does not remove any 2025-11-25-specific behavior, omitting it creates an interop regression for current clients.
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Summary
Content-Lengthframing with the MCP stdio transport's newline-delimited JSON on both output and input parsing, so conforming MCP clients no longer hang against the server.protocolVersionin theinitializehandler: echo a supported client version back, otherwise respond with the latest supported version (2025-06-18, replacing the unpublished2025-11-25).-32700parse error response instead of crashing the data handler.Closes #68
Test plan
node tests/integrations/runtime-mcp-contract.mjspasses, including new protocolVersion negotiation assertions and a stdio smoke test performing a real newline-delimited JSON handshake (initialize -> notifications/initialized -> tools/list) against a spawned server process./scripts/check.shpasses from the repo root🤖 Generated with Claude Code