[mkatariya90]

Description

Adds examples/scripts/nemo_relay, a tutorial for agent builders: a Deep Agents agent whose every tool call NeMo Relay checks with NeMo Guardrails' Relay plugin and nemoguardrails hooks-server.

• Policy (configs/policy, model-free): a tool and argument allowlist with allow_unlisted_tools: false (no shell, no delete), and CEL rules that cap read_log at 500 lines and allow http_request only as a GET to https://*.internal.example. configs/policy_judge adds an LLM-judged tool safety check on http_request for secrets in allowed requests.
• relay_plugin.py: activates the plugin for a block of code, with startup = "required", so a plugin that doesn't load stops the agent instead of leaving calls unchecked.
• deny_feedback.py: middleware that hands a deny back to the model as ToolMessage(status="error"), so the agent corrects the call. A failed check propagates, and the run stops.
• agent.py: passes Deep Agents' built-in general-purpose subagent to add_nemo_relay_integration explicitly. Deep Agents doesn't give it the main agent's middleware, so without this its tool calls run unchecked.
• README: step-by-step tutorial, with each control mapped to the OWASP Top 10 for LLM Applications 2025 and for Agentic Applications 2026.

Supporting changes: a deepagents_example_hooks_server fixture in integration_tests/relay_plugin/conftest.py, deepagents added to the hash-locked relay plugin test requirements, and cross-links from the plugin docs and integration_tests/README.md.

Areas for careful review:

• integration_tests/relay_plugin/requirements.txt was regenerated with deepagents; it may conflict with fix(deps): bump pytest from 9.1.1 to 9.2.0 in /integration_tests/relay_plugin in the relay-plugin-tests group #2579 if that merges first.
• The OWASP mapping in the README's "OWASP Coverage" section.
• Denies and failed checks are told apart by Relay's RuntimeError message prefixes (guardrail rejected: and internal error: NeMo Guardrails check failed for tool call). A typed exception from Relay would make this sturdier.

Related Issue(s)

• Fixes feature: Deep Agents example for checking tool calls with NeMo Relay and the hooks server #2590
• Issue assignee: @mkatariya90

Verification

• make test TEST=tests/server/test_hooks_nemo_relay_example.py: 23 passed.
• integration_tests/relay_plugin (whole suite, through the built plugin): 43 passed, including the 7 new Deep Agents tests.
• ruff check, ruff format --check, license headers, and ty check: pass.
• The same policy and wiring were exercised in a larger Deep Agents demo against a live NIM model, with both configs, including stopping the hooks server mid-run.
• Not run: agent.py in its final form against a live model (CI drives it with a scripted model), and the docs build.

AI Assistance

• No AI tools were used.
• AI tools were used; a human reviewed and can explain every change (tool: Cursor).

Checklist

• I've read the CONTRIBUTING guidelines.
• This PR links to a triaged issue assigned to me.
• My PR title follows the project commit convention.
• I've updated the documentation if applicable.
• I've added tests if applicable.
• I've noted any verification beyond CI and any checks I couldn't run.
• I did not update generated changelog files manually.
• I addressed all CodeRabbit, Greptile, and other review comments, or replied with why no change is needed.
• @mentions of the person or team responsible for reviewing proposed changes.

@Pouyanpi @tgasser-nv

[github-actions]

Staged Fern docs preview: https://nvidia-preview-pr-2591.docs.buildwithfern.com/nemo/guardrails