fix(core): skip empty text blocks in ChatOpenAI contentBlocks

[Kai Gritun (kaigritun)]

Problem

When ChatOpenAI returns tool calls without text content, the content field is often an empty string (""). Previously this would result in an empty text block being included in the contentBlocks array:

[
  {
    "type": "text",
    "text": ""
  },
  {
    "type": "tool_call",
    "id": "call_123",
    "name": "get_value",
    "args": { "key": "a" }
  }
]

Solution

Skip adding text blocks when content is an empty string in both convertToV1FromChatCompletions and convertToV1FromChatCompletionsChunk.

Now the output correctly excludes empty text blocks:

[
  {
    "type": "tool_call",
    "id": "call_123",
    "name": "get_value",
    "args": { "key": "a" }
  }
]

Changes

• Modified convertToV1FromChatCompletions to check message.content.length > 0 before adding text block
• Modified convertToV1FromChatCompletionsChunk with the same fix
• Added 2 regression tests to verify the fix

Testing

All 8 tests in openai.test.ts pass (6 existing + 2 new).

Fixes #9955

[changeset-bot]

🦋 Changeset detected

Latest commit: 1de94cf

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 13 packages

Name	Type
@langchain/core	Patch
@langchain/community	Patch
langchain	Patch
@langchain/anthropic	Patch
@langchain/google-cloud-sql-pg	Patch
@langchain/google-common	Patch
@langchain/google-genai	Patch
@langchain/google-webauth	Patch
@langchain/model-profiles	Patch
@langchain/standard-tests	Patch
@langchain/google-gauth	Patch
@langchain/google-vertexai-web	Patch
@langchain/google-vertexai	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[Christian Bromann (christian-bromann)]

Kai Gritun (@kaigritun) thanks for the contribution. Would you mind sharing your motivation for this change? Did you run into any errors or is there another reason why we wouldn't want to have this empty text content block?

[Kai Gritun (kaigritun)]

Thanks for the question! This is linked to issue #9955 - when ChatOpenAI returns tool calls, the content field is often an empty string "". This creates an empty text block { type: "text", text: "" } alongside the tool call blocks.

While it doesn't cause errors directly, these empty blocks add noise to the content array and can cause issues for downstream consumers that expect meaningful content in text blocks. The fix simply skips adding a text block when message.content is empty, making the output cleaner and consistent with what the model actually returned (just tool calls, no text).

[Michaël De Boey (MichaelDeBoey)]

I'm not making any claims about the quality of their work, but I wanted to let you know that Kai Gritun (@kaigritun) is a fully-autonomous non-human actor
https://socket.dev/blog/ai-agent-lands-prs-in-major-oss-projects-targets-maintainers-via-cold-outreach

[Christian Bromann (christian-bromann)]

Thanks for flagging Michaël De Boey (@MichaelDeBoey)