[codex] add Grok Build capability probe

docs/tests/report-grok-build-capability.md

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+# Grok Build Capability Probe
+
+Date: 2026-05-18T10:45:34Z
+Suite: tests/test-grok-build-capability
+Runtime target: grok-build-acp / grok-build-cli
+Verdict: **Wait**
+
+## Summary
+
+- PASS: 2
+- FAIL: 0
+- SKIP: 7
+- WARN: 0
+- grok version: `grok 0.1.211 (2f2cd6d5c)`
+- Credential: `GROK_CODE_XAI_API_KEY` missing
+
+## Results
+
+| Probe | Status | Detail |
+|---|---|---|
+
+| grok --version | PASS | grok 0.1.211 (2f2cd6d5c) |
+| permission default | PASS | --always-approve is explicit; probe did not enable it |
+| API-key-only headless | SKIP | GROK_CODE_XAI_API_KEY not provided |
+| grok -p final answer | SKIP | requires GROK_CODE_XAI_API_KEY |
+| streaming-json schema | SKIP | requires GROK_CODE_XAI_API_KEY |
+| session resume | SKIP | requires GROK_CODE_XAI_API_KEY |
+| temp repo file edit | SKIP | requires GROK_CODE_XAI_API_KEY |
+| ACP stdio | SKIP | requires GROK_CODE_XAI_API_KEY |
+| MCP no-op tool | SKIP | requires GROK_CODE_XAI_API_KEY |
+
+## Fixtures
+
+- streaming JSON: `docs/tests/fixtures/grok-build/streaming-json.jsonl`
+- JSON final: `docs/tests/fixtures/grok-build/final.json`
+- ACP stdio: `docs/tests/fixtures/grok-build/acp-stdio.jsonl`
+- MCP no-op: `docs/tests/fixtures/grok-build/mcp-noop.jsonl`
+
+## Notes
+
+- This suite installs Grok Build inside Docker using the official installer URL: `https://x.ai/cli/install.sh`.
+- If `GROK_CODE_XAI_API_KEY` is absent, authenticated probes are skipped and the verdict remains Wait.
+- The probe does not enable `--always-approve` by default. Permission behavior is inspected separately.

tests/test-grok-build-capability/Dockerfile

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+FROM node:20-slim
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+  bash \
+  ca-certificates \
+  coreutils \
+  curl \
+  git \
+  jq \
+  procps \
+  sed \
+  tar \
+  unzip \
+  xz-utils \
+  && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /probe
+COPY tests/test-grok-build-capability/run.sh /probe/run.sh
+RUN chmod +x /probe/run.sh
+
+CMD ["/probe/run.sh"]

tests/test-grok-build-capability/README.md

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+# Grok Build Capability Probe
+
+This suite validates whether Grok Build can be used as an Agent Network runtime.
+
+Run from the repository root:
+
+```bash
+sg docker -c 'docker build -t agent-network-grok-probe -f tests/test-grok-build-capability/Dockerfile .'
+sg docker -c 'docker run --rm -e GROK_CODE_XAI_API_KEY="$GROK_CODE_XAI_API_KEY" -v "$PWD/docs/tests:/work/docs/tests" agent-network-grok-probe'
+```
+
+Without `GROK_CODE_XAI_API_KEY`, authenticated checks are marked `SKIP` and the verdict remains `Wait`.