docs: Add Scalekit integration for authenticated tool calling

[saif-at-scalekit (saif-at-scalekit)]

Summary

Add Scalekit as a LangSmith integration under Developer tools.

Scalekit provides authenticated tool calling for AI agents — 60+ pre-built connectors
(Gmail, Slack, Salesforce, GitHub, Notion, etc.) with delegated OAuth, token management, and native LangChain
StructuredTool support. When LangSmith tracing is enabled, Scalekit tool calls appear as tool spans automatically.

Files changed

• src/langsmith/trace-with-scalekit.mdx — new integration page (SDK adapter + MCP methods)
• src/images/providers/light/scalekit.svg — provider icon (light mode)
• src/images/providers/dark/scalekit.svg — provider icon (dark mode)
• src/langsmith/integrations.mdx — added Scalekit card to Developer tools grid
• src/docs.json — added nav entry

Testing

Code examples verified with traces received in LangSmith UI.
See scalekit-developers/agent-auth-examples#3 for the tested script.

References

• Scalekit AgentKit docs
• Scalekit LangChain guide
• Sample LangChain agent repo
• Package: scalekit-sdk-python

[github-actions]

Thanks for opening a docs PR, saif-at-scalekit (@saif-at-scalekit)! When it's ready for review, please add the relevant reviewers:

• @katmayb or @fjmorris (LangSmith)

[github-actions]

❌ Import check failed

This PR contains imports from langchain_core that should be imported from langchain instead.

Detailed issues

Analyzing diff for import issues...
 Found 2 import issues:

File: src/langsmith/trace-with-scalekit.mdx
Line: 97
Issue: Import from langchain.messages instead of langchain_core.messages
Current:   from langchain_core.messages import HumanMessage, ToolMessage
Suggested: from langchain.messages import HumanMessage, ToolMessage
--------------------------------------------------------------------------------
File: src/langsmith/trace-with-scalekit.mdx
Line: 147
Issue: Import from langchain.messages instead of langchain_core.messages
Current:   from langchain_core.messages import HumanMessage, ToolMessage
Suggested: from langchain.messages import HumanMessage, ToolMessage
--------------------------------------------------------------------------------

 Found 2 import issues that need to be fixed.

Why this is a problem

The langchain package re-exports many modules and classes from langchain_core. When possible, imports should use langchain instead of langchain_core for:

• Better user experience (single import source)
• Consistency across documentation
• Reduced cognitive load for users

How to fix

Replace the imports as suggested above. For example:

• ❌ from langchain_core.messages import HumanMessage
• ✅ from langchain.messages import HumanMessage

🤖 Automated check

This check is based on the latest analysis of langchain re-exports from langchain_core.

[saif-at-scalekit (saif-at-scalekit)]

Addressed the import issue that's pointed out by github actions.

[saif-at-scalekit (saif-at-scalekit)]

Kathryn May (@katmayb) / Florence Morris (@fjmorris) – I’ve gone through other PRs and the contribution guidelines to this pull request. Since this is my first time working on this PR and on #3963, I may have missed a few things. Please let me know if there’s anything I can adjust to make this PR as clean as possible and straightforward for you to review and merge.