Docs: document nat serve /health endpoint in REST API guide

Problem

nat serve now exposes a FastAPI GET /health endpoint, but the public REST API server endpoints guide does not mention it. The guide lists the workflow/chat routes and shows how to start nat serve, but an operator looking for a liveness/readiness URL has no documented route to use.

Self-hosted/operator use case

When running NeMo Agent Toolkit workflows behind a reverse proxy, process supervisor, Docker healthcheck, or Kubernetes-style readiness/liveness probe, I need a stable documented endpoint that can be checked without sending an actual workflow request or requiring model/API credentials.

The MCP and FastMCP server guides already document their health checks, so the FastAPI nat serve path feels like the missing piece for production deployment docs.

Evidence inspected

• Current published REST API server endpoints guide: https://docs.nvidia.com/nemo/agent-toolkit/latest/reference/rest-api/api-server-endpoints.html
  • Documents /v1/workflow, /v1/workflow/stream, /v1/workflow/full, /v1/workflow/async, /v1/chat, /v1/chat/stream, /v1/chat/completions, and legacy paths.
  • Does not mention /health, liveness, or readiness.
• Local source on develop: packages/nvidia_nat_core/src/nat/front_ends/fastapi/routes/health.py
  • Registers GET /health.
  • Returns {"status": "healthy"} with HTTP 200.
  • Description says Health check endpoint for liveness/readiness probes.
• Merged PR that added the endpoint: https://github.com/NVIDIA/NeMo-Agent-Toolkit/pull/1466
  • PR body says: Add GET /health endpoint to nat serve for liveness/readiness probes. Returns {"status": "healthy"} with 200 status code.
• MCP health docs already exist:
  • https://docs.nvidia.com/nemo/agent-toolkit/latest/run-workflows/mcp-server.html documents /health and nat mcp client ping.
  • https://docs.nvidia.com/nemo/agent-toolkit/latest/run-workflows/fastmcp-server.html documents /health and nat mcp client ping.

Expected behavior

The REST API server endpoints documentation should include the FastAPI server health route, probably near "Default Endpoint Paths" or "Start the NeMo Agent Toolkit Server":

curl -s http://localhost:8000/health

Expected response:

{"status":"healthy"}

It would also help to state that this is intended for liveness/readiness probes and does not execute a workflow.

Suggested implementation shape

Small docs-only update:

1. Add GET /health to docs/source/reference/rest-api/api-server-endpoints.md.
2. Mention that it returns HTTP 200 with {"status":"healthy"}.
3. Cross-link, if desired, from the serving/deployment section or REST endpoint table.
4. Optionally add an explicit note that MCP/FastMCP have separate health-check docs and default ports.

Duplicate search performed

I searched open and recent closed issues/PRs before filing:

• Pulled 24 open issues, 200 closed issues, 20 open PRs, and 200 closed PRs with gh.
• Searched GitHub for: health endpoint, healthcheck, readiness probe, liveness probe, nat serve health, MCP health, FastMCP health, deployment health, monitoring health, reverse proxy health, Kubernetes health, docker health, and production health.
• Relevant hits found:
  • #1466 added the FastAPI /health endpoint, but did not add it to the current REST API endpoints guide.
  • #576 added MCP /health docs/behavior.
  • #1539 added FastMCP support and current FastMCP health docs.
• I did not find an open documentation issue covering the missing nat serve /health documentation.

Willingness to contribute

Happy to open a small docs PR for this if maintainers agree the REST API endpoints guide is the right place.