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fix(memory): strip type field from entities/relations in loadGraph#3094

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jared03 wants to merge 2 commits intomodelcontextprotocol:mainfrom
jared03:fix/memory-schema-validation
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fix(memory): strip type field from entities/relations in loadGraph#3094
jared03 wants to merge 2 commits intomodelcontextprotocol:mainfrom
jared03:fix/memory-schema-validation

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@jared03
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@jared03 jared03 commented Dec 1, 2025

Summary

Fixes schema validation error in read operations (read_graph, search_nodes, open_nodes).

Problem

The JSONL file stores entities with a type field to distinguish them from relations:

{"type":"entity","name":"...","entityType":"...","observations":[...]}

But the output schema only expects {name, entityType, observations} - no type field.

This causes all read operations to fail with:

MCP error -32602: Structured content does not match the tool's output schema: data.entities[0] should NOT have additional properties

Solution

Strip the type field using destructuring before pushing to result arrays:

if (item.type === "entity") {
  const { type, ...entity } = item;
  graph.entities.push(entity as Entity);
}
if (item.type === "relation") {
  const { type, ...relation } = item;
  graph.relations.push(relation as Relation);
}

Testing

  • All 39 existing tests pass
  • All read operations now return valid responses
  • Write operations continue to work correctly
  • Existing JSONL files remain fully compatible

Fixes #3074

@jared03
fix(memory): strip type field from entities/relations in loadGraph
48fc103 
The JSONL file stores entities with a 'type' field to distinguish them
from relations. However, the output schema for read operations doesn't
include this field, causing schema validation errors (-32602).

This fix uses destructuring to remove the 'type' field before pushing
entities and relations to the result arrays.

Fixes modelcontextprotocol#3074
@YuGe-Git
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YuGe-Git commented Dec 6, 2025

你好 @jared03，感谢你修复这个问题！🙏

我正在 Cursor IDE 中使用 @modelcontextprotocol/server-memory，遇到了 #3074 中描述的问题。所有的读操作（read_graph、search_nodes、open_nodes）都会报错：

MCP error -32602: Structured content does not match the tool's output schema: 
data.entities[0] should NOT have additional properties

由于这个 PR 还未合并，修复还没有发布到 npm 包中，导致我无法在 Cursor 中正常使用 memory MCP 服务器。

问题：

  1. 这个 PR 预计何时会合并？
  2. 合并后，预计何时会发布新版本到 npm？
  3. 在此期间有什么临时解决方案吗？（目前我只能在避免使用读操作，只使用写操作）

感谢你的工作！期待使用修复后的版本。🚀

@sha1sum
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sha1sum commented Dec 20, 2025

I'd love to see this make it in. My MCP calls are not working right now.

@pout8
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pout8 commented Dec 26, 2025

似乎还需要有仓库权限的人审批。

@aarongrtech
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aarongrtech commented Jan 12, 2026

I independently discovered this same bug and implemented the identical fix. Can confirm this is the correct solution.

Root cause: loadGraph() pushes items directly from JSONL including the type discriminator field, but the output schema (EntitySchema/RelationSchema) doesn't include type, causing strict JSON Schema validation to reject the response.

The fix is correct: Destructuring to strip type mirrors what saveGraph() does when writing (it explicitly constructs objects with only schema-defined fields).

This also fixes #3144 which reports the same error.

+1 for merge - this is blocking all read operations for anyone using the memory server.

@aarongrtech aarongrtech mentioned this pull request Jan 12, 2026
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Memory MCP, schema validation error: MCP error -32602

5 participants

@jared03 @YuGe-Git @sha1sum @pout8 @aarongrtech