NVIDIA/NeMo-Relay is a runtime and library that gives coding agents and applications shared control over agent execution scopes, policies, plugins, lifecycle events, and observability data. It is for developers who need to inspect or instrument runs from agents such as Codex or Claude Code, or integrate frameworks and export traces and trajectories. The catalogue entries provide Relay plugins, hooks, instructions, skills, and an MCP server for those workflows.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add hooks/nvidia/nemo-relay/user-prompt-expansiongit clone --depth 1 https://github.com/NVIDIA/NeMo-RelayWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/hooks/nvidia/nemo-relay/user-prompt-expansion)<a href="https://agentmods.dev/hooks/nvidia/nemo-relay/user-prompt-expansion"><img src="https://agentmods.dev/badge/hooks/nvidia/nemo-relay/user-prompt-expansion.svg" alt="Measured on agentmods" height="20"></a>Grade A, and why
UserPromptExpansion scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.
A static scan of the commands this hook runs, not an audit. A hook is shell that executes on your machine at the event it names, which is why every command in it is printed with what was found.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
This is a copy
89% identical to SessionStart — 2 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
What it actually says
{
"UserPromptExpansion": [
{
"hooks": [
{
"type": "command",
"command": "nemo-relay hook-forward claude --gateway-url http://127.0.0.1:47632 --forward-only --fail-open",
"timeout": 30
}
]
}
]
}What else hooks.json configures
This page is one entry in a file that holds 14. Installing the file brings all of them; each is measured and scanned on its own page.
- Hook Notification A not measured
- Hook PermissionRequest A not measured
- Hook PostCompact A not measured
- Hook PostToolUse A not measured
- Hook PostToolUseFailure A not measured
- Hook PreCompact A not measured
- Hook PreToolUse A not measured
- Hook SessionEnd A not measured
- Hook SessionStart A not measured
- Hook Stop A not measured
- Hook SubagentStart A not measured
- Hook SubagentStop A not measured
- Hook UserPromptSubmit A not measured
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 5d ago First seen · 13 lines scan A 163a3a0460a1
UserPromptExpansion is a hook published in the GitHub repository NVIDIA/NeMo-Relay (162 stars, last pushed today), licensed Apache-2.0. Its token cost is not measured: a hook is shell that never enters the context. A static security scan graded it A with 0 findings. It is 89% identical to SessionStart, differing in 2 lines, and is treated as a copy.
Other hooks, from other repositories
SubagentStop
Runs when a subagent finishes, executing tlc-cleanup.sh and continuous-execution-hook.sh via bash (2 commands). From johanolofsson72/Claude.
PostToolUse
Runs after a tool call finishes for Write and Edit tool calls, executing format_and_lint.sh. From supabase/supabase.
SessionStart
Runs when a session starts, executing on-start.js via node. From google-gemini/gemini-cli.
SessionStart
Runs when a session starts on startup, executing install_pkgs.sh. From supabase/supabase.
PreToolUse
Runs before the agent uses a tool for Bash tool calls, running an inline shell check. From apache/superset.
PreToolUse
Runs before the agent uses a tool, executing pre-write.sh and pre-bash.sh (2 commands). From anthropics/claude-cookbooks.