Fix #2356: l3.abstraction: misleading "title must be a non-empty string" error — output tru

[Memtensor-AI]

Description

Fixed the misleading "title must be a non-empty string" error in L3 world-model generation caused by two cooperating bugs.

Bug 1 — extractFirstJsonBlock (json-mode.ts): The old loop continued scanning for a nested balanced sub-block when the root opener returned null from walkToClose. A truncated root object like {"title":"...","domain_tags":["network","http"],... left the root { unbalanced, causing the loop to continue and find the inner domain_tags array, which was fully balanced. JSON.parse then succeeded on that array, and the caller's validate() received ["network","http","local-services","cron"] instead of the full object — correctly reporting 'title' must be a non-empty string but pointing blame at the model rather than at token truncation. Fix: stop at the first opener; if walkToClose returns null, return null immediately.

Bug 2 — completeJson (client.ts): finishReason === "length" was already present on LlmCompletion but completeJson passed the truncated text straight to parseLlmJson without inspecting it. Fix: check finishReason === "length" before parsing; throw LLM_OUTPUT_MALFORMED immediately with finishReason: "length" and rawLen in the error details. Also added rawLen to all existing malformed warn log rows for easier token-budget diagnosis.

Tests: 5 new test cases added (2 in json-mode.test.ts, 3 in client.test.ts). All 43 LLM unit tests pass. Pre-existing failures in subscriber.test.ts are unrelated (SQLite native binding absent in this environment).

Related Issue (Required): Fixes #2356

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (does not change functionality, e.g. code style improvements, linting)
• Documentation update

How Has This Been Tested?

Automated tests are pending.

• Unit Test
• Test Script Or Test Steps (please provide)
• Pipeline Automated API Test (please provide)

Checklist

• I have performed a self-review of my own code
• I have commented my code in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works
• I have created related documentation issue/PR in MemOS-Docs (if applicable)
• I have linked the issue to this PR (if applicable)
• I have mentioned the person who will review this PR

@whipser030, @hijzy please review this PR.

Reviewer Checklist

• closes l3.abstraction: misleading "title must be a non-empty string" error — output truncation at maxTokens, parseLlmJson falls back to a nested block #2356
• Made sure Checks passed
• Tests have been provided

[Memtensor-AI]

🤖 Open Code Review

Target: PR #2357
Task: 035ad74cb9dcd82a
Base: dev-v2.0.34
Head: bugfix/autodev-2356-20260910132328679
Head SHA: 4ce26cc592ef6c63c9417e6e7a55fb0d38c54baa

🔍 OpenCodeReview found 1 issue(s) in this PR.

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1. apps/memos-local-plugin/core/llm/client.ts (L543-L546)

retries is not declared anywhere in the completeJson function scope — only attempt is. Referencing retries++ here will throw a ReferenceError at runtime whenever a truncated response is received, crashing the retry path entirely instead of retrying. The existing parse-error branch below uses attempt (not retries) for its own continue, which is the correct pattern. Either remove retries++ entirely (since attempt already tracks the iteration count and is checked by the while condition), or declare let retries = 0 alongside the other loop variables at the top of the function if a separate counter is intentionally needed.

💡 Suggested Change

Before:

        if (attempt <= maxMalformedRetries) {
          retries++;
          continue;
        }

After:

        if (attempt <= maxMalformedRetries) {
          continue;
        }

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[Memtensor-AI]

🔧 Open Code Review requested Agent fix

Open Code Review found 1 issue(s). I have resumed the development Agent to fix them.

• Task: 035ad74cb9dcd82a
• Fix attempt: 1/2
• Finding delta: 0 repeated / 1 new / 0 likely resolved

The Agent will push a new commit to this PR branch. OCR will recheck after the commit is pushed.