fix: support Zod runtimes that store literal values in _def.values[0]#1665
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Vadaski wants to merge 2 commits intomodelcontextprotocol:mainfrom
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fix: support Zod runtimes that store literal values in _def.values[0]#1665Vadaski wants to merge 2 commits intomodelcontextprotocol:mainfrom
Vadaski wants to merge 2 commits intomodelcontextprotocol:mainfrom
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…modelcontextprotocol#1380) buildSchemaMap accessed schema.shape.method.value directly. In Zod runtimes that store literal values only in _def.values[0] (with neither the top-level .value shortcut nor _def.value present), this would throw "Schema method literal must be a string" during McpServer construction. Added getMethodLiteral() helper that reads the literal value from .value ?? ._def?.value ?? ._def?.values?.[0], and updated buildSchemaMap to use this helper. Fixes modelcontextprotocol#1380 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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@modelcontextprotocol/client
@modelcontextprotocol/server
@modelcontextprotocol/express
@modelcontextprotocol/hono
@modelcontextprotocol/node
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Problem
buildSchemaMapinpackages/core/src/types/types.tsreadsschema.shape.method.valuedirectly. In some Zod runtimes (particularly certain Zod 3.25.x releases), literal values are stored only in._def.values[0], with neither the top-level.valueproperty nor._def.valuepresent. This causesMcpServerconstruction to fail with:Steps to Reproduce
With a Zod runtime where literal schemas lack the
.valueshortcut, constructingnew McpServer({ name: 'my-server', version: '1.0' })throws the above error.Fix
Added
getMethodLiteral()helper that tries all three locations where a literal value may be stored:schema.value(standard Zod shortcut)schema._def.value(Zod v3 internal)schema._def.values[0](Zod 3.25.x variant)Updated
buildSchemaMapto use this helper instead of direct.valueaccess.Testing
Added a regression test at
test/integration/test/issues/test1380.zod.literal-values.test.tsthat mockszod/v4to expose literal schemas with only_def.values[0](hiding both.valueand._def.value), then verifiesnew McpServer(...)does not throw.Fixes #1380