diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index ee11d48..989184b 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -179,7 +179,12 @@ jobs:
           cd "$SCRATCH" && git init -q
           python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" preflight --json | jq -e '.ok == true'
           python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" init --dir docs/decisions --json | jq -e '.ok == true'
+          echo '{"title":"Parity Test ADR","status":"proposed","body":"Testing harness parity expansion."}' > draft.json
+          python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" create --input draft.json --dir docs/decisions --json | jq -e '.ok == true'
           python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" validate --dir docs/decisions --json | jq -e '.ok == true'
+          python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" search --keyword "Parity" --dir docs/decisions --json | jq -e '.ok == true'
+          python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" graph --dir docs/decisions --json | jq -e '.ok == true'
+          python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" check --dir docs/decisions --json | jq -e '.ok == true'
       - name: Verify Antigravity CLI adapter end to end
         run: |
           set -euo pipefail
@@ -196,7 +201,12 @@ jobs:
           cd "$SCRATCH" && git init -q
           python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" preflight --json | jq -e '.ok == true'
           python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" init --dir docs/decisions --json | jq -e '.ok == true'
+          echo '{"title":"Parity Test ADR","status":"proposed","body":"Testing harness parity expansion."}' > draft.json
+          python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" create --input draft.json --dir docs/decisions --json | jq -e '.ok == true'
           python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" validate --dir docs/decisions --json | jq -e '.ok == true'
+          python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" search --keyword "Parity" --dir docs/decisions --json | jq -e '.ok == true'
+          python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" graph --dir docs/decisions --json | jq -e '.ok == true'
+          python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" check --dir docs/decisions --json | jq -e '.ok == true'
       - name: Verify Gemini CLI adapter end to end
         run: |
           set -euo pipefail
@@ -212,4 +222,9 @@ jobs:
           cd "$SCRATCH" && git init -q
           python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" preflight --json | jq -e '.ok == true'
           python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" init --dir docs/decisions --json | jq -e '.ok == true'
+          echo '{"title":"Parity Test ADR","status":"proposed","body":"Testing harness parity expansion."}' > draft.json
+          python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" create --input draft.json --dir docs/decisions --json | jq -e '.ok == true'
           python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" validate --dir docs/decisions --json | jq -e '.ok == true'
+          python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" search --keyword "Parity" --dir docs/decisions --json | jq -e '.ok == true'
+          python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" graph --dir docs/decisions --json | jq -e '.ok == true'
+          python3 "$INSTALLED_PATH/skills/adr-toolkit/scripts/adr.py" check --dir docs/decisions --json | jq -e '.ok == true'
diff --git a/changelog.md b/changelog.md
index b1ead37..544828f 100644
--- a/changelog.md
+++ b/changelog.md
@@ -4,6 +4,7 @@ Lightweight human-readable summary of meaningful repository changes.
 
 ## Unreleased
 
+- Expanded `harness-parity` CI job to verify `create`, `search`, `graph`, and `check` commands across Codex, Antigravity, and Gemini CLI adapters (#28).
 - Added step-by-step tutorial for adding new harness adapters in `adapters/README.md` (#33).
 - Added `docs/factual-correction-policy.md` defining in-place metadata correction vs. decision superseding policy for Accepted ADRs (#29).
 - Modernized PyPA license metadata in `pyproject.toml` to SPDX expression (`license = "MIT"`) and `license-files` (#30).
diff --git a/handoff.md b/handoff.md
index 3af0095..dc3f61c 100644
--- a/handoff.md
+++ b/handoff.md
@@ -2,6 +2,11 @@
 
 ## Current task
 
+Resolving GitHub Issue #28 (`Test: harness parity를 check/search/graph/create까지 확장`). Branch `feature/issue-28-harness-parity-expansion`.
+
+## Touched files
+
+- `.github/workflows/test.yml` — expanded `harness-parity` CI job to verify `create`, `search`, `graph`, and `check` commands across Codex, Antigravity, and Gemini CLI adapters.
 Resolving GitHub Issues #33 (`Docs: adapters/README.md tutorial`) and #29 (`Docs: Accepted ADR metadata factual-correction policy`). Branch `docs/issue-33-29-docs-and-policy`.
 
 ## Touched files
@@ -15,10 +20,13 @@ Resolving GitHub Issues #33 (`Docs: adapters/README.md tutorial`) and #29 (`Docs
 ## Verification
 
 - `scripts/sync_version.py --check`: **exit 0**
+- `.github/workflows/test.yml` YAML syntax validated: **exit 0**
 - `git status` clean and verified.
 
 ## Next step
 
+1. Complete merge of `origin/develop` into `feature/issue-28-harness-parity-expansion` and push.
+2. Verify PR #52 merge status on GitHub.
 1. Merge PR #51 into `develop`.
 2. Proceed to PR #52 and PR #53 merges.
 
diff --git a/improvements.md b/improvements.md
index 8a0f201..bf9a93a 100644
--- a/improvements.md
+++ b/improvements.md
@@ -67,6 +67,7 @@ Backlog derived from `docs/adr-toolkit-audit-report.md`, operational experiences
 
 ## Done
 
+- [x] **harness parity CI 검증 명령 확장** — Codex/Antigravity/Gemini어댑터에 대해 `create`, `search`, `graph`, `check` 명령 검증 추가 (#28).
 - [x] **'새 harness adapter 추가하기' 튜토리얼 작성** — `adapters/README.md` 가이드 및 규격 정리 완료 (#33).
 - [x] **Accepted ADR metadata factual-correction policy 설계** — `docs/factual-correction-policy.md` 정책 문서 정의 완료 (#29).
 - [x] **PyPA license metadata 현대화** — SPDX 표현식 (`license = "MIT"`) 및 `license-files = ["LICENSE*"]` 적용 완료 (#30).