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Fix MCP error responses missing jsonrpc field #1931

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Merged
arrufat merged 1 commit into from
Mar 20, 2026
+8 −8
Merged

Fix MCP error responses missing jsonrpc field #1931

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6 changes: 3 additions & 3 deletions src/mcp/Server.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -87,7 +87,7 @@ pub fn sendResult(self: *Self, id: std.json.Value, result: anytype) !void {
}

pub fn sendError(self: *Self, id: std.json.Value, code: protocol.ErrorCode, message: []const u8) !void {
try self.sendResponse(.{
try self.sendResponse(protocol.Response{
.id = id,
.@"error" = protocol.Error{
.code = @intFromEnum(code),
Expand All @@ -114,7 +114,7 @@ test "MCP.Server - Integration: synchronous smoke test" {

try router.processRequests(server, &in_reader);

try testing.expectJson(.{ .id = 1 }, out_alloc.writer.buffered());
try testing.expectJson(.{ .jsonrpc = "2.0", .id = 1 }, out_alloc.writer.buffered());
}

test "MCP.Server - Integration: ping request returns an empty result" {
Expand All @@ -135,5 +135,5 @@ test "MCP.Server - Integration: ping request returns an empty result" {

try router.processRequests(server, &in_reader);

try testing.expectJson(.{ .id = "ping-1", .result = .{} }, out_alloc.writer.buffered());
try testing.expectJson(.{ .jsonrpc = "2.0", .id = "ping-1", .result = .{} }, out_alloc.writer.buffered());
}
10 changes: 5 additions & 5 deletions src/mcp/router.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -120,30 +120,30 @@ test "MCP.router - handleMessage - synchronous unit tests" {
\\{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test-client","version":"1.0.0"}}}
);
try testing.expectJson(
\\{ "id": 1, "result": { "capabilities": { "tools": {} } } }
\\{ "jsonrpc": "2.0", "id": 1, "result": { "capabilities": { "tools": {} } } }
, out_alloc.writer.buffered());
out_alloc.writer.end = 0;

// 2. Ping
try handleMessage(server, aa,
\\{"jsonrpc":"2.0","id":2,"method":"ping"}
);
try testing.expectJson(.{ .id = 2, .result = .{} }, out_alloc.writer.buffered());
try testing.expectJson(.{ .jsonrpc = "2.0", .id = 2, .result = .{} }, out_alloc.writer.buffered());
out_alloc.writer.end = 0;

// 3. Tools list
try handleMessage(server, aa,
\\{"jsonrpc":"2.0","id":3,"method":"tools/list"}
);
try testing.expectJson(.{ .id = 3 }, out_alloc.writer.buffered());
try testing.expectJson(.{ .jsonrpc = "2.0", .id = 3 }, out_alloc.writer.buffered());
try testing.expect(std.mem.indexOf(u8, out_alloc.writer.buffered(), "\"name\":\"goto\"") != null);
out_alloc.writer.end = 0;

// 4. Method not found
try handleMessage(server, aa,
\\{"jsonrpc":"2.0","id":4,"method":"unknown_method"}
);
try testing.expectJson(.{ .id = 4, .@"error" = .{ .code = -32601 } }, out_alloc.writer.buffered());
try testing.expectJson(.{ .jsonrpc = "2.0", .id = 4, .@"error" = .{ .code = -32601 } }, out_alloc.writer.buffered());
out_alloc.writer.end = 0;

// 5. Parse error
Expand All @@ -152,6 +152,6 @@ test "MCP.router - handleMessage - synchronous unit tests" {
defer filter.deinit();

try handleMessage(server, aa, "invalid json");
try testing.expectJson("{\"id\": null, \"error\": {\"code\": -32700}}", out_alloc.writer.buffered());
try testing.expectJson("{\"jsonrpc\": \"2.0\", \"id\": null, \"error\": {\"code\": -32700}}", out_alloc.writer.buffered());
}
}
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