examples/mcp: add HashLock OTC remote MCP example

[BarisSozen]

What

Adds a minimal, self-contained example that connects the Agents SDK to HashLock OTC's remote MCP server (https://mcp.hashlock.markets/mcp) over Streamable HTTP. The agent requests an OTC crypto quote and streams quotes back from institutional market makers.

Why

HashLock exposes atomic HTLC settlement via MCP. Including it alongside the existing HTTP examples gives developers a realistic non-toy integration to copy from.

Scope

• examples/mcp/hashlock_example/main.py — ~55 LOC, mirrors the style of streamable_http_remote_example
• examples/mcp/hashlock_example/README.md — setup + token instructions
• No library code changes

Safety note

The example is explicit that on-chain HTLC writes should not be triggered from the agent loop. That matches HashLock's own design: settlement signatures happen out-of-band in the user's browser wallet.

How I tested

Locally with HASHLOCK_ACCESS_TOKEN set:

python examples/mcp/hashlock_example/main.py
# -> streams quotes from the RFQ

Checklist

• Added to examples/mcp/ directory
• README included
• No new dependencies beyond openai-agents and stdlib
• Works out of the box once HASHLOCK_ACCESS_TOKEN is set

[seratch]

Thanks for sharing this. While we don't include this example in this repo, please feel fee to share it in your own repo.