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fix(memory): allow additional properties in entity/relation schemas#3161

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majiayu000 wants to merge 1 commit intomodelcontextprotocol:mainfrom
majiayu000:fix/memory-schema-additional-properties
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fix(memory): allow additional properties in entity/relation schemas#3161
majiayu000 wants to merge 1 commit intomodelcontextprotocol:mainfrom
majiayu000:fix/memory-schema-additional-properties

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@majiayu000
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@majiayu000 majiayu000 commented Dec 28, 2025

Summary

Problem

When memory.jsonl contains entities with extra properties (e.g., custom_id), the read_graph tool fails with:

MCP error -32602: Structured content does not match the tool's output schema: 
data/entities/0 must NOT have additional properties

Solution

Using Zod's .passthrough() allows the schema to accept additional properties while still validating required fields.

Fixes #3144

@majiayu000
fix(memory): allow additional properties in entity/relation schemas
dacdf62 
Added .passthrough() to EntitySchema and RelationSchema to allow
entities with extra properties to be read without schema validation
errors. This fixes the issue where read_graph fails when the stored
memory.jsonl contains entities with non-standard properties.

Fixes modelcontextprotocol#3144

Signed-off-by: majiayu000 <1835304752@qq.com>
@NeverMore93
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NeverMore93 commented Dec 30, 2025

The issue is not resolved

@majiayu000
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majiayu000 commented Dec 30, 2025

@NeverMore93 I've tested this fix and verified it works correctly. Here's my analysis:

Root Cause:
The validation error occurs on the client side, not the server side. When the server returns structuredContent, the MCP client validates it against the outputSchema using AJV (JSON Schema validator).

  • Without .passthrough(): JSON Schema has additionalProperties: false → validation fails
  • With .passthrough(): JSON Schema has additionalProperties: {} → validation passes

Test Results:
I reproduced the issue and confirmed the fix works:

# Before fix (additionalProperties: false)
Error: MCP error -32602: Structured content does not match the tool's output schema: 
data/entities/0 must NOT have additional properties

# After fix (additionalProperties: {})
SUCCESS! read_graph returns data with extra properties correctly

Could you share more details about your test environment?

  • MCP SDK version (npm list @modelcontextprotocol/sdk)
  • The exact error message you're seeing
  • Steps to reproduce the issue

This will help identify if there's a version-specific issue or a different scenario not covered by this fix.

@cardmagic cardmagic mentioned this pull request Dec 31, 2025
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Memory MCP Schema Validation Error on read_graph for entities with additional properties

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@majiayu000 @NeverMore93