ai: apply changes for #862 (1 review thread)

Addresses:
  - #3599241197 at .github/actions/install-bot-engine/action.yml:58

Author: peco-engineer-bot[bot]

.github/actions/install-bot-engine/action.yml

@@ -70,13 +70,21 @@ runs:
         if [ -z "$ACCESS_TOKEN" ] || [ "$ACCESS_TOKEN" = "null" ]; then
           echo "::error::Could not extract JFrog access token (is id-token:write granted?)"; exit 1
         fi
-        echo "PIP_INDEX_URL=https://gha-service-account:${ACCESS_TOKEN}@databricks.jfrog.io/artifactory/api/pypi/db-pypi/simple" >> "$GITHUB_ENV"
-        cat > ~/.npmrc << EOF
+        # Do NOT export the token-bearing index URL to $GITHUB_ENV or write it to
+        # ~/.npmrc: either would leak the embedded credential into the environment
+        # of every LATER step in the job (the author/publish/comment steps that run
+        # the model and `gh`). Instead stash both creds in JOB-LOCAL files (0600)
+        # under RUNNER_TEMP; the install step below loads them into its own step-local
+        # environment and removes them in its EXIT trap — the same scope-and-cleanup
+        # discipline the git extraheader already uses.
+        umask 077
+        printf '%s\n' "https://gha-service-account:${ACCESS_TOKEN}@databricks.jfrog.io/artifactory/api/pypi/db-pypi/simple" > "${RUNNER_TEMP:-/tmp}/bot-jfrog-pip-index"
+        cat > "${RUNNER_TEMP:-/tmp}/bot-jfrog-npmrc" << EOF
         registry=https://databricks.jfrog.io/artifactory/api/npm/db-npm/
         //databricks.jfrog.io/artifactory/api/npm/db-npm/:_authToken=${ACCESS_TOKEN}
         always-auth=true
         EOF
-        echo "JFrog mirror configured for pip + npm"
+        echo "JFrog mirror configured for pip + npm (job-local creds)"
 
     - name: Install engine (pinned REF) + Claude SDK/CLI
       shell: bash
@@ -110,13 +118,26 @@ runs:
         echo "::add-mask::${BASIC}"
         export GIT_CONFIG_GLOBAL="${RUNNER_TEMP:-/tmp}/bot-engine-gitconfig-$$"
         : > "$GIT_CONFIG_GLOBAL"
-        trap 'git config --global --unset-all "http.https://github.com/.extraheader" || true; rm -f "$GIT_CONFIG_GLOBAL"' EXIT
+        # Job-local JFrog creds written by the mirror step above (if any). Load the
+        # pip index into a per-command flag and point npm at the job-local .npmrc,
+        # so neither credential lands in $GITHUB_ENV / ~/.npmrc for later steps.
+        JFROG_PIP_INDEX_FILE="${RUNNER_TEMP:-/tmp}/bot-jfrog-pip-index"
+        JFROG_NPMRC_FILE="${RUNNER_TEMP:-/tmp}/bot-jfrog-npmrc"
+        trap 'git config --global --unset-all "http.https://github.com/.extraheader" || true; rm -f "$GIT_CONFIG_GLOBAL" "$JFROG_PIP_INDEX_FILE" "$JFROG_NPMRC_FILE"' EXIT
         git config --global "http.https://github.com/.extraheader" "Authorization: Basic ${BASIC}"
-        python -m pip install --upgrade pip
+        PIP_ARGS=()
+        NPM_ARGS=()
+        if [ -s "$JFROG_PIP_INDEX_FILE" ]; then
+          PIP_ARGS=(--index-url "$(cat "$JFROG_PIP_INDEX_FILE")")
+        fi
+        if [ -s "$JFROG_NPMRC_FILE" ]; then
+          NPM_ARGS=(--userconfig "$JFROG_NPMRC_FILE")
+        fi
+        python -m pip install "${PIP_ARGS[@]}" --upgrade pip
         # REF mode resolves the published engine's deps unpinned + installs the
         # SDK/CLI by version (a consumer can't see the engine's hash-locked
         # requirements). SDK_VERSION/CLI_VERSION track the engine at ENGINE_REF.
-        pip install "databricks-bot-engine @ git+https://github.com/${ENGINE_REPO}@${ENGINE_REF}"
-        pip install "claude-agent-sdk==${SDK_VERSION}"
-        npm install -g "@anthropic-ai/claude-code@${CLI_VERSION}"
+        pip install "${PIP_ARGS[@]}" "databricks-bot-engine @ git+https://github.com/${ENGINE_REPO}@${ENGINE_REF}"
+        pip install "${PIP_ARGS[@]}" "claude-agent-sdk==${SDK_VERSION}"
+        npm install "${NPM_ARGS[@]}" -g "@anthropic-ai/claude-code@${CLI_VERSION}"
         echo "$(npm prefix -g)/bin" >> "$GITHUB_PATH"