docs: add Modexia AgentPay tool integration

[Daniel Okinda (Modaniels)]

Overview

Added documentation for the new langchain-modexia integration, bringing Modexia AgentPay capabilities (autonomous crypto payments, cross-chain transfers, and X402 paywall negotiation) to LangChain agents. Added the new tool to the tools index page.

Type of change

Type: New documentation page / Update existing documentation

Related issues/PRs

• GitHub issue: N/A
• Feature PR: N/A

• Linear issue: N/A
• Slack thread: N/A

Checklist

• I have read the contributing guidelines, including the language policy
• I have tested my changes locally using docs dev
• All code examples have been tested and work correctly
• I have used root relative paths for internal links
• I have updated navigation in src/docs.json if needed

(Internal team members only / optional): Create a preview deployment as necessary using the Create Preview Branch workflow

Additional notes

The integration uses the langchain-modexia package. Note that the integration also provides JavaScript/TypeScript support via Model Context Protocol (MCP), which is mentioned in the documentation.

[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 1 import issues:

File: src/oss/python/integrations/tools/modexia.mdx
Line: 157
Issue: Import from langchain.messages instead of langchain_core.messages
Current:   from langchain_core.messages import HumanMessage
Suggested: from langchain.messages import HumanMessage
--------------------------------------------------------------------------------

 Found 1 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.

[Copilot]

Pull request overview

Adds LangChain OSS (Python) documentation for the new langchain-modexia integration (Modexia AgentPay) and surfaces it in the Python tools index so users can discover and use the tool.

Changes:

• Added a new tool documentation page for Modexia AgentPay, including setup, instantiation, invocation, chaining, and agent usage examples.
• Added Modexia AgentPay to the Python tools index (Finance table + All tools cards).
• Updated src/code-samples/package-lock.json (lockfile metadata changes).

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 4 comments.

File	Description
src/oss/python/integrations/tools/modexia.mdx	New integration doc page describing Modexia AgentPay tools and usage patterns.
src/oss/python/integrations/tools/index.mdx	Adds Modexia AgentPay to the tools listing for discoverability.
src/code-samples/package-lock.json	Lockfile metadata changes included in the PR.

Files not reviewed (1)

• src/code-samples/package-lock.json: Language not supported

[Copilot]

This PR is primarily adding docs, but src/code-samples/package-lock.json is also being modified (e.g., removing "peer": true entries). If this lockfile change isn’t required for the Modexia docs, consider reverting it to keep the PR focused and reduce merge-churn.

[Daniel Okinda (Modaniels)]

changed the tool feature