> For clean Markdown of any page, append .md to the page URL. > For a complete documentation index, see https://docs.nvidia.com/nemo/relay/llms.txt. > For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.nvidia.com/nemo/relay/_mcp/server. # Coding Agent Installation > Install and manage persistent NeMo Relay integrations for Claude Code, Codex, and Hermes Agent. Install a persistent integration when you want Claude Code, Codex, or Hermes Agent to load NeMo Relay without a `nemo-relay` wrapper command. Claude Code and Codex use their normal plugin systems. Hermes uses the same native MCP lifecycle through its user configuration without a marketplace plugin. Each persistent integration forwards the lifecycle signals that its host exposes, including agent, subagent, tool, prompt, compaction, and stop events where available. Model-provider routing sends LLM traffic through the local NeMo Relay gateway. Hooks alone cannot capture complete LLM request and response spans. All three integrations share the same lifecycle gateway. Provider traffic joins that gateway when routing is configured for the host: ```text Codex / Claude Code / Hermes Agent |-> Relay MCP lifecycle client -------> shared Relay gateway |-> generated lifecycle hooks --------> shared Relay gateway \-> provider route (when configured) -> shared Relay gateway -> model provider ``` Each agent starts its own lightweight MCP stdio process. Those processes share one compatible gateway. Generated lifecycle hooks use `hook-forward` to deliver their canonical payloads to that same gateway. ## Requirements Install `nemo-relay` and ensure that it is available on `PATH` or `%PATH%`. The installer does not download a second Relay binary, install a daemon, or require an integration-local executable. The selected coding-agent CLI must also be available at a supported version: * Claude Code 2.1.121 or newer through `claude`. * `codex-cli` 0.143.0 or newer through `codex`. * Hermes Agent 0.18.2 or newer through `hermes`. Relay checks the selected CLI version before modifying agent configuration. Prerelease, malformed, and older versions are rejected consistently by install, doctor, and transparent launch paths. ## Install a Persistent Integration Run the command for the coding-agent integration that you want to install: ```bash nemo-relay install claude-code nemo-relay install codex nemo-relay install hermes ``` Install every supported host detected on the machine: ```bash nemo-relay install all ``` `install all` selects only supported agents whose CLI is present. It fails if Claude Code, Codex, and Hermes Agent are all absent. Use `--dry-run` to preview the operation without changing host configuration. For Claude Code and Codex, the preview includes marketplace paths and host commands. For Hermes, it shows the user configuration path: ```bash nemo-relay install codex --dry-run ``` For Claude Code and Codex, use `--install-dir` when you need a non-default marketplace location. Hermes always updates its user configuration. The default plugin directory is platform-specific: | Platform | Default Plugin Install Directory | | -------- | ----------------------------------------------------- | | macOS | `~/Library/Application Support/nemo-relay/plugins` | | Linux | `${XDG_DATA_HOME:-~/.local/share}/nemo-relay/plugins` | | Windows | `%LOCALAPPDATA%\nemo-relay\plugins` | Relay serializes install, force-install, rollback, and uninstall operations for each user and host, even when two operations name different install directories. If another operation is still active after a short wait, Relay stops with a timeout instead of changing host-wide plugin state concurrently. ## What Install Changes For Claude Code and Codex, `nemo-relay install` writes a local marketplace named `nemo-relay-local`, then registers the generated `nemo-relay-plugin` package with the selected host. For Claude Code, `nemo-relay install claude-code` registers the local marketplace, installs `nemo-relay-plugin@nemo-relay-local` at user scope, and enables provider routing through the local NeMo Relay sidecar. Relay preserves existing Claude authentication and model settings and backs them up only when it adds the provider route. The plugin also declares the native `nemo-relay mcp` lifecycle client. For Codex, `nemo-relay install codex` registers the local marketplace, installs `nemo-relay-plugin@nemo-relay-local`, enables Codex hooks, and configures the `nemo-relay-openai` provider alias at `http://127.0.0.1:47632`. The plugin's `hooks/hooks.json` is the sole persistent Relay hook source. The installer uses the Codex app-server API to select hooks by plugin ID, exact canonical command, and event definition. It never trusts unrelated user, project, or plugin hooks. If Codex does not discover exactly one enabled and trusted handler for every generated event—`SessionStart`, `UserPromptSubmit`, `PreToolUse`, `PostToolUse`, `PermissionRequest`, `SubagentStart`, `SubagentStop`, `Stop`, `PreCompact`, and `PostCompact`—installation restores the previous Codex config, legacy hooks, Relay backup files, and every original targeted trust entry. These 10 events are the complete supported Codex 0.143 plugin hook schema; Relay does not generate undiscoverable `PostToolUseFailure`, `Notification`, or `SessionEnd` handlers. Upgrade removes legacy Relay groups from `~/.codex/hooks.json` while preserving unrelated hooks. For Hermes, `nemo-relay install hermes` adds the Relay MCP server, canonical hooks, exact hook trust, and environment references to `$HERMES_HOME/config.yaml`, or `~/.hermes/config.yaml` when `HERMES_HOME` is unset. Relay applies these changes in one transaction and preserves unrelated Hermes configuration. Refer to the [Hermes Agent guide](/nemo-relay-cli/hermes). On Windows, generated hooks use the built-in Windows PowerShell encoded-command format. This avoids quoting and metacharacter differences between the Codex, Claude Code, and Hermes command runners. The encoded payload contains only the canonical `nemo-relay.exe` path and `hook-forward` arguments. PowerShell starts that Rust binary directly and preserves its standard input, standard output, standard error, and exit code. The MCP client and gateway remain Rust-native, and both install and doctor verify the generated command and event ownership. Start a new Codex CLI process after installation. Restart the Codex desktop app if it was already running so it reloads the provider and hook configuration. ### Shared Gateway Lifecycle Claude Code, Codex, and configured Hermes processes use the same `nemo-relay mcp` lifecycle client. Before reading MCP protocol frames, it starts or reuses a detached native sidecar on `127.0.0.1:47632`. The client verifies Relay identity, version, protocol readiness, and effective user-level configuration, then heartbeats the sidecar every 30 seconds. Concurrent processes from any host share the gateway. After the final MCP client closes, the sidecar exits after 300 idle seconds by default. If the gateway exits while MCP stdio is open, the client performs one coordinated restart and fails if recovery does not succeed. Relay reports a port conflict for a foreign process instead of accepting it merely because it returned HTTP 200. Health and readiness responses include a per-process instance ID. A per-user startup lock serializes launch and recovery, while a small recovery record lets overlapping MCP clients share the same restart attempt. The gateway tracks its own activity, idle shutdown, and authenticated ownership-record cleanup. Codex marks the MCP server as required, so the captured turn waits for verified gateway readiness. Claude Code 2.1.121 or newer uses `alwaysLoad`, which blocks session startup until the MCP connection is ready. Hermes starts MCP discovery asynchronously, so its first lifecycle hook can arrive before MCP is ready. Installed MCP entries and `hook-forward` commands carry both the generation-file path and the immutable identity expected at that path. This prevents a host process with cached plugin configuration from adopting a replacement installation after `--force`. Persistent hooks wait for the MCP-owned gateway, verify it on the same connection used for delivery, and send the canonical payload once. They never start or recover the gateway, and Relay does not retry after payload transmission begins. The MCP server advertises no tools in any host. ### Hook Delivery and Upgrade Safety Before contacting the gateway, Relay rejects a fixed-endpoint `hook-forward` command that lacks a valid installer-owned generation fence. It uses the configured hook failure policy. This prevents a legacy hook retained by a host process from reviving a retired installation. If install or uninstall reports a missing or invalid generation marker, follow its cleanup instructions: close the host and standalone `nemo-relay mcp` processes, remove the stale registration and state it identifies, and then run the requested `--force` command. Transparent hooks embed their process-private gateway URL and never recover a persistent gateway, so they do not need this fence. Source plugins and custom automation can use `--forward-only` to contact an existing gateway without a fence. That mode waits for an authenticated, configuration-compatible Relay gateway and rejects foreign or incompatible listeners before it sends the payload. Authentication and delivery use the same TCP connection, so a process that replaces the listener after a health probe cannot receive lifecycle data. The mode never launches or recovers Relay. Relay cannot guarantee exactly-once delivery if the gateway fails after it accepts a request. It does not keep a durable hook outbox or deduplication journal. The opt-in end-to-end tests verify exactly-once lifecycle output for the healthy and cold-start paths they exercise, not for arbitrary crashes between request acceptance and response delivery. On Windows, Relay requests Job Object breakaway when the host job permits it. When breakaway is unavailable and the host permits nested assignment, the gateway remains scoped to the host job and can exit before the normal idle reuse window. If the host rejects nested assignment, persistent bootstrap stops and explains the conflict instead of running without process-tree cleanup guarantees. The compatibility fingerprint covers resolved provider, exporter, dynamic plugin, and relevant environment settings without exposing their values in the health response. For Claude Code and Codex, `nemo-relay install --force` rotates the immutable MCP and hook generation identity, then uses a private ownership token to stop the shared fixed-endpoint gateway as one serialized operation. Ownership is keyed by endpoint rather than host, so an upgrade from any installed host can retire a gateway that another host originally started. Relay leaves custom managed endpoints untouched and never sends its shutdown token to an unrelated listener. Hermes installation rotates its MCP generation fence in the same transaction. ### Configuration and Credentials Persistent mode resolves only system and user Relay configuration and starts in the user configuration directory. Project `.nemo-relay` layers remain available through transparent `nemo-relay run` invocations. Each host passes environment settings to MCP differently: * Codex stores variable names—not values—for provider credentials, Relay runtime, OpenTelemetry, AWS, proxies, certificates, approved prefixes, and credential variables referenced by user observability configuration. * Claude Code supplies its normal plugin MCP environment. * Hermes stores `${VARIABLE_NAME}` references for the standard allowlist, custom variables that you have already approved, and credential names referenced by user observability configuration. Relay treats unresolved self-references as unset before parsing its command line. Rerun `nemo-relay install hermes --force` after you add a custom approved name or change a credential name referenced by the configuration. The long-lived managed sidecar injects a forwarded provider credential only when a request carries provider authorization or Relay's private per-user client proof. The Codex installer writes a domain-separated HMAC proof into the managed provider's `http_headers`; Relay stores the resulting Codex config with an owner-only mode on Unix or protected owner/System DACL on Windows before the temporary file becomes visible. Relay validates and removes that header before middleware, observability, or upstream forwarding. The underlying HMAC key remains in Relay's owner-only bootstrap state. Claude Code and Hermes send their normal provider authorization. A foreign loopback caller cannot spend the sidecar's forwarded credentials. Foreground `nemo-relay --bind` use retains environment-key injection for explicit local proxy workflows. ## Diagnose Run the command for the installed integration that you want to diagnose: ```bash nemo-relay doctor --plugin claude-code nemo-relay doctor --plugin codex nemo-relay doctor --plugin hermes nemo-relay doctor --plugin all ``` `nemo-relay doctor` includes every persistent integration it finds. It checks generated marketplace and plugin files where applicable, the Relay binary and hook support, agent version, registration, provider routing, hooks, and sidecar readiness assumptions. For Codex, doctor also asks the Codex app-server whether each exact Relay-generated hook is trusted and enabled. JSON output includes `checks.codex_hooks_trusted` and a `codex_hook_trust` object that groups trusted, untrusted, modified, disabled, missing, or duplicated required hooks. A stopped Codex sidecar is informational; the required plugin MCP starts it before the captured turn. Doctor also reports newly required forwarded environment names and recommends `nemo-relay install codex --force`. For Claude Code, doctor also validates version 2.1.121 or newer, the generated `alwaysLoad` MCP server, and its generation marker. A stopped sidecar remains informational because the next MCP process starts it. Persistent hooks wait for that MCP-owned gateway instead of starting it themselves. For Hermes, doctor validates Hermes Agent 0.18.2 or newer. It reads the Relay executable from the managed Hermes MCP entry, verifies that exact executable supports both `mcp` and `hook-forward`, and then checks every hook and trust pair, the generation marker, and environment references. Top-level `nemo-relay doctor` discovers this managed state directly from the Hermes user configuration; an `[agents.hermes]` Relay configuration block is not required. Use the focused plugin doctor when diagnosing one host or an installation that uses a custom directory: ```bash nemo-relay doctor --plugin codex --install-dir /path/to/plugins ``` If an installed integration is incomplete, doctor reports the failed check and suggests `nemo-relay install --force`. Agents without a persistent installation remain informational, so transparent-run setup does not require one. ## Uninstall Run the command for the installed integration that you want to remove: ```bash nemo-relay uninstall claude-code nemo-relay uninstall codex nemo-relay uninstall hermes nemo-relay uninstall all ``` Uninstall removes Codex provider configuration and trust for the exact plugin hooks before unregistering the plugin, while Codex can still report its hook metadata. It then removes the host registration and marketplace. Claude Code provider routing is restored from the Relay backup. Unrelated user hooks and configuration remain unchanged. Hermes uninstall removes only Relay-owned MCP, hook, trust, and generation state. ## Compatibility and Migration These integrations now require Codex 0.143.0, Claude Code 2.1.121, or Hermes Agent 0.18.2 at minimum. Relay rejects prerelease or malformed version output. If you configured an opaque wrapper, its `--version` output must identify the selected host. Interactive `nemo-relay config hermes` now owns only transparent-wrapper configuration; use `nemo-relay install hermes` and `nemo-relay uninstall hermes` for persistent Hermes state. The MCP bootstrap is now host-neutral. Generated Codex, Claude Code, and Hermes configuration invokes `nemo-relay mcp`; the removed `--agent` option no longer parses. Existing fenced installations can be refreshed with `nemo-relay install --force`. Relay refuses to replace an older MCP installation without a valid generation marker because a cached host process might still be running. In that case, follow the manual cleanup steps in the error before you retry the forced install. This release removes the internal `nemo-relay plugin-shim` command. Refresh a fenced generated installation with `nemo-relay install --force`; use the manual cleanup described above when its generation marker is missing. For custom automation, use these supported replacements: | Removed Internal Command | Supported Replacement | | ------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------- | | `nemo-relay plugin-shim hook ` | `nemo-relay hook-forward --forward-only` with the canonical lifecycle payload on standard input and an existing gateway | | `nemo-relay plugin-shim serve` | `nemo-relay mcp` for host-managed lifecycle, or `nemo-relay --bind
` to run a gateway directly | | `nemo-relay plugin-shim install ` | `nemo-relay install ` | | `nemo-relay plugin-shim uninstall ` | `nemo-relay uninstall ` | | `nemo-relay plugin-shim provider claude enable` | `nemo-relay install claude-code` | | `nemo-relay plugin-shim provider claude restore` | `nemo-relay uninstall claude-code` | | `nemo-relay plugin-shim provider claude status` | `nemo-relay doctor --plugin claude-code` | | `nemo-relay plugin-shim doctor ` | `nemo-relay doctor --plugin ` | Persistent generated hook commands include the fixed gateway URL. Transparent wrapper hooks embed their dynamic gateway URL, while the process environment lets an installed plugin MCP authenticate, borrow, and monitor that exact gateway. Transparent hook delivery authenticates the wrapper gateway before writing its lifecycle payload. When a transparent run uses a recognizable wrapper command, such as `npx codex`, Relay checks the host version through that wrapper. Opaque custom wrappers remain supported when the configured command emits the selected host's canonical version output in response to `--version`. Install and doctor enforce the same minimum-version policy. Hermes setup uses the same public install, doctor, and uninstall commands as Claude Code and Codex. `nemo-relay config hermes` configures Relay's transparent wrapper only; it no longer mutates Hermes user configuration. Use `nemo-relay install hermes` for the persistent host integration. ## Source Marketplace Discovery This repository also contains source marketplace manifests for development and validation: * `.claude-plugin/marketplace.json` * `.agents/plugins/marketplace.json` Those manifests are useful when validating host plugin metadata from a source checkout. For end-user setup, use `nemo-relay install `. For Claude Code and Codex, the command generates the local marketplace, registers the host plugin, and performs the required provider and hook setup. Source manifests do not provide Codex's complete provider, environment-forwarding, and verified-trust workflow. Do not keep a source-installed plugin and the generated plugin active for the same host. Both can forward the same lifecycle payload and produce duplicate events. Remove the source-installed plugin before you use the generated install.