diff --git a/.env.example b/.env.example
index a800f537..1f151b70 100644
--- a/.env.example
+++ b/.env.example
@@ -83,6 +83,37 @@ ROBOCO_LOCAL_LLM_BASE_URL=http://localhost:11434/v1
 ROBOCO_LOCAL_LLM_MODEL=glm-5:cloud
 ROBOCO_DEFAULT_EMBEDDING_MODEL=qwen3-embedding:0.6b
 
+# =============================================================================
+# Grok (xAI) Provider — optional
+# =============================================================================
+# RoboCo can run agents on grok-build-0.1 (xAI) via the opencode runtime instead
+# of Claude Code. The xAI API key is NOT set here — store it encrypted per
+# project from the panel (provider key), the same as the Ollama/Anthropic keys.
+# Every var below is optional; defaults shown.
+
+# Image the orchestrator spawns for Grok agents.
+# ROBOCO_GROK_AGENT_IMAGE=roboco-agent-grok:latest
+
+# opencode tool permissions for Grok agents: allow | ask | deny. Defaults are
+# "allow"; tighten bash to "deny"/"ask" to fail closed on untrusted repos (the
+# secret-scrub plugin is a denylist, not a full sandbox).
+# ROBOCO_GROK_BASH_PERMISSION=allow
+# ROBOCO_GROK_EDIT_PERMISSION=allow
+# ROBOCO_GROK_EXTERNAL_DIR_PERMISSION=allow
+
+# Force one reasoning effort for ALL Grok agents: minimal | high | max (or empty
+# for opencode's default). Empty = per-role: coordination/docs roles request
+# "minimal" to cut reasoning cost, code roles keep full reasoning.
+# ROBOCO_GROK_REASONING_EFFORT=
+
+# Kill a Grok agent container after this many seconds idle (no model call /
+# stream) to reclaim a wedged one. Minimum 120.
+# ROBOCO_GROK_IDLE_KILL_SECONDS=900
+
+# Per-agent cost ceiling (USD) before the orchestrator kills the container;
+# 0 disables. Backstops runaway-loop token burn.
+# ROBOCO_GROK_MAX_COST_USD=0.0
+
 # =============================================================================
 # Security
 # =============================================================================
diff --git a/docker/agent-grok.Dockerfile b/docker/agent-grok.Dockerfile
index b4098b0e..7fa0ec82 100644
--- a/docker/agent-grok.Dockerfile
+++ b/docker/agent-grok.Dockerfile
@@ -15,7 +15,10 @@ USER root
 # opencode — the OpenAI-protocol agent runtime. grok-build-0.1 runs on opencode's
 # BUILT-IN xai provider (no custom provider block / npm needed), so only
 # opencode-ai is installed; it resolves the provider SDK at runtime.
-RUN npm install -g opencode-ai \
+# Pinned: this version is the live-verified runtime (grok-build-0.1 on the NAS).
+# Untrusted model output runs under it, so bump the pin deliberately, never float.
+ARG OPENCODE_VERSION=1.17.8
+RUN npm install -g "opencode-ai@${OPENCODE_VERSION}" \
     && npm cache clean --force \
     && rm -rf /root/.npm /tmp/*
 
diff --git a/docker/grok/budget-feed.js b/docker/grok/budget-feed.js
index 1f66d4af..257346f8 100644
--- a/docker/grok/budget-feed.js
+++ b/docker/grok/budget-feed.js
@@ -18,10 +18,13 @@
 //           terminal verb is recognized) and /budget/tool_called (advances the
 //           breaker/loop counters and feeds the post-exit post-mortem).
 //
-// Fail-open everywhere: a missing / slow / non-2xx SDK never blocks the agent.
-// The interactive serve images (intake / secretary) own :9000 for the human-turn
-// receiver and run NO SDK server, so these POSTs 404 there and are ignored —
-// those roles don't claim tasks or loop on verbs, so they need no budget feed.
+// Fail policy: the `after` POSTs never block (recording can't risk spend). The
+// `before` gate fails OPEN by default, but fails CLOSED when ROBOCO_BUDGET_ENFORCE=1
+// (set by the one-shot entrypoint, which always starts the SDK budget server) and
+// the budget server is unreachable — an unenforceable cost cap on a task agent is
+// the one case worth halting for. Interactive serve images (intake / secretary)
+// own :9000 for the human-turn receiver, run NO SDK budget server, and set no
+// ENFORCE flag, so their tool calls always proceed (these POSTs 404 there).
 
 const SDK_URL = process.env.ROBOCO_SDK_URL || "http://localhost:9000";
 
@@ -68,7 +71,8 @@ function argsHash(args) {
 // the Claude path's verbs arrive bare. Strip a known roboco-* server prefix so
 // the SDK recognizes a terminal verb (i_am_idle / i_am_done / ...) — the SDK's
 // own "__"-split is a no-op on the already-bare verb this returns.
-// UNVERIFIED-LIVE: opencode's exact MCP tool-name shape; the strip is defensive.
+// Verified live: opencode delivers MCP tools as "roboco-flow_<verb>" (underscore);
+// the "." form and an mcp__ prefix are still handled defensively.
 function bareVerb(tool) {
   const mcp = tool.match(/^mcp__[a-z0-9-]+__(.+)$/);
   if (mcp) return mcp[1];
@@ -84,7 +88,19 @@ export const RobocoBudgetFeed = async () => {
   return {
     "tool.execute.before": async (input) => {
       const status = await sdk("GET", "/budget/status", null);
-      if (!status) return; // fail-open
+      if (!status) {
+        // One-shot delivery agents MUST have the in-container SDK budget server
+        // (the entrypoint starts it and exports ENFORCE=1). A missing signal
+        // there means the cost cap is unenforceable — fail CLOSED to stop an
+        // uncapped burn. Interactive serve agents set no flag → fail open.
+        if (process.env.ROBOCO_BUDGET_ENFORCE === "1") {
+          throw new Error(
+            "[Halt] budget server unreachable — failing closed to prevent " +
+              "uncapped token spend. Stop now with i_am_idle() or unclaim().",
+          );
+        }
+        return; // fail-open (no budget server expected for this role)
+      }
       if (status.halt) {
         throw new Error(
           `[Halt] tool budget exhausted (${status.total}/${status.halt_threshold}). ` +
diff --git a/docker/grok/secret-scrub.js b/docker/grok/secret-scrub.js
index b24386ba..eb86ccd3 100644
--- a/docker/grok/secret-scrub.js
+++ b/docker/grok/secret-scrub.js
@@ -10,12 +10,13 @@
 // command is `output.args.command`; for `read`/`edit` the path is
 // `output.args.filePath`.
 //
-// Loaded via the generated opencode.json `plugin:` array (see
-// roboco.llm.providers.opencode_config). The agent's bash permission can also
-// be set to "deny"/"ask" via ROBOCO_GROK_BASH_PERMISSION as a second gate.
+// Baked into the plugin auto-discovery dir (~/.config/opencode/plugin/) at image
+// build (named export, opencode's convention) — the same route as budget-feed.
+// The agent's bash permission is a second gate via ROBOCO_GROK_BASH_PERMISSION.
 //
-// STATUS: unvalidated against a live opencode runtime. Confirm it actually
-// fires in the live E2E spawn before pointing a Grok dev-agent at a real repo.
+// STATUS: the plugin loads in the live runtime (same auto-discovery dir as the
+// live-confirmed budget-feed), but the deny-on-match path has not yet blocked a
+// real command on the NAS — confirm before trusting it as the sole bash gate.
 // Deny-on-match is fail-closed: a false positive blocks a legitimate command
 // (annoying, safe) rather than letting a dangerous one through.
 
diff --git a/docker/grok/secretary-tools.js b/docker/grok/secretary-tools.js
index fcabf3b0..0900e55e 100644
--- a/docker/grok/secretary-tools.js
+++ b/docker/grok/secretary-tools.js
@@ -18,9 +18,9 @@
 // forwards the call. Each tool returns the backend JSON as a string the model
 // reads back (mirrors secretary_driver._text_result).
 //
-// UNVERIFIED-LIVE: the @opencode-ai/plugin tool-registration path against a live
-// opencode serve + grok-build-0.1 — confirm a submit_directive round-trips with
-// the HMAC token on the NAS before routing real CEO directives through Grok.
+// Verified live on the NAS: the @opencode-ai/plugin tool-registration path
+// round-trips against a live opencode serve + grok-build-0.1 — a directive
+// reaches the backend with the HMAC token and the JSON result returns to the model.
 
 import { tool } from "@opencode-ai/plugin";
 
diff --git a/docker/scripts/grok-agent-entrypoint.sh b/docker/scripts/grok-agent-entrypoint.sh
index 6ac6e18e..a0d67a78 100755
--- a/docker/scripts/grok-agent-entrypoint.sh
+++ b/docker/scripts/grok-agent-entrypoint.sh
@@ -33,6 +33,12 @@ fi
 # Zero the budget/terminal counters at the start of the session.
 curl -sf -m 2 -X POST "${SDK_URL}/budget/reset" >/dev/null 2>&1 || true
 
+# This is a one-shot delivery agent: the SDK budget server above is mandatory.
+# Tell the budget-feed plugin to FAIL CLOSED if that server ever goes
+# unreachable mid-run, so an unenforceable cost cap halts the burn instead of
+# letting it run uncapped. (Interactive serve images set no such flag.)
+export ROBOCO_BUDGET_ENFORCE=1
+
 # Prompt-injection guard (parity with the Claude UserPromptSubmit hook): the
 # task prompt is DATA, not instructions — refuse a poisoned one before it
 # reaches the model. Same patterns as docker/scripts/user-prompt-hook.sh.