[v1.x backport] fix(server): respect explicit listChanged: false in McpServer#1937
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Zelys-DFKH wants to merge 2 commits intomodelcontextprotocol:v1.xfrom
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[v1.x backport] fix(server): respect explicit listChanged: false in McpServer#1937Zelys-DFKH wants to merge 2 commits intomodelcontextprotocol:v1.xfrom
Zelys-DFKH wants to merge 2 commits intomodelcontextprotocol:v1.xfrom
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…ity registration Backport of modelcontextprotocol#1513 to v1.x. The three lazy-init methods in McpServer (setToolRequestHandlers, setResourceRequestHandlers, setPromptRequestHandlers) unconditionally registered listChanged: true when called, overwriting any explicit listChanged: false passed in capabilities at construction time. Fixed by reading the current capability value via Server.getCapabilities() and applying it with nullish coalescing so that undefined still defaults to true (backwards compatible), but explicit false is preserved. Also made Server.getCapabilities() public to allow McpServer to read it. Fixes modelcontextprotocol#1819
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Summary
Backport of #1513 to
v1.x.Constructing
McpServerwithcapabilities: { tools: { listChanged: false } }had no effect. The three lazy-init methods (setToolRequestHandlers,setResourceRequestHandlers,setPromptRequestHandlers) each callregisterCapabilitieswith a hardcodedlistChanged: true, overwriting whatever the user passed at construction time. Stateless servers can't opt out of list-change notifications onv1.x.Root cause (
src/server/mcp.ts:134,496,576):this.server.registerCapabilities({ - tools: { listChanged: true } + tools: { listChanged: this.server.getCapabilities().tools?.listChanged ?? true } });Same fix applied to
resourcesandprompts.Server.getCapabilities()changed fromprivatetopublicsoMcpServercan read the current value. The?? truedefault keeps existing behavior for servers that don't setlistChangedat all.Test plan
Added 4 tests to
test/server/mcp.test.ts, run against both Zod v3 and v4 viadescribe.each:should default tools.listChanged to true when not explicitly setshould respect tools.listChanged: false when explicitly setshould respect resources.listChanged: false when explicitly setshould respect prompts.listChanged: false when explicitly set6 of 8 fail on pre-fix code (the default test passes on both Zod variants; the three false-respecting tests fail). All 8 pass after. Full suite: 1587/1587, no regressions.
Fixes #1819