diff --git a/actions/setup/js/action_setup_otlp.cjs b/actions/setup/js/action_setup_otlp.cjs
index c84b1760067..a7ff441d3e7 100644
--- a/actions/setup/js/action_setup_otlp.cjs
+++ b/actions/setup/js/action_setup_otlp.cjs
@@ -30,6 +30,20 @@ const { appendFileSync } = require("fs");
 const { nowMs } = require("./performance_now.cjs");
 const { getActionInput } = require("./action_input_utils.cjs");
 
+/**
+ * Append a key=value line to a GitHub Actions file (GITHUB_OUTPUT or GITHUB_ENV)
+ * if the file path is set and the value is truthy.
+ * @param {string | undefined} filePath - Path to the output/env file
+ * @param {string} key - The variable name
+ * @param {string} value - The value to write
+ * @param {string} logLabel - Label used in the confirmation log message
+ */
+function writeEnvLine(filePath, key, value, logLabel) {
+  if (!filePath || !value) return;
+  appendFileSync(filePath, `${key}=${value}\n`);
+  console.log(`[otlp] ${logLabel} written to ${filePath === process.env.GITHUB_OUTPUT ? "GITHUB_OUTPUT" : "GITHUB_ENV"}`);
+}
+
 /**
  * Send the OTLP job-setup span and propagate trace context via GITHUB_OUTPUT /
  * GITHUB_ENV.  Non-fatal: all errors are silently swallowed.
@@ -90,38 +104,25 @@ async function run() {
     console.log(`[otlp] setup span sent (traceId=${traceId}, spanId=${spanId})`);
   }
 
+  const githubOutput = process.env.GITHUB_OUTPUT;
+  const githubEnv = process.env.GITHUB_ENV;
+
   // Always expose trace ID as a step output for cross-job correlation, even
   // when OTLP is not configured.  This ensures needs.*.outputs.setup-trace-id
   // is populated for downstream jobs regardless of observability configuration.
-  if (isValidTraceId(traceId) && process.env.GITHUB_OUTPUT) {
-    appendFileSync(process.env.GITHUB_OUTPUT, `trace-id=${traceId}\n`);
-    console.log(`[otlp] trace-id=${traceId} written to GITHUB_OUTPUT`);
-  }
-  if (isValidSpanId(spanId) && process.env.GITHUB_OUTPUT) {
-    appendFileSync(process.env.GITHUB_OUTPUT, `span-id=${spanId}\n`);
-    console.log(`[otlp] span-id=${spanId} written to GITHUB_OUTPUT`);
-  }
-  if (isValidSpanId(parentSpanId) && process.env.GITHUB_OUTPUT) {
-    appendFileSync(process.env.GITHUB_OUTPUT, `parent-span-id=${parentSpanId}\n`);
-    console.log(`[otlp] parent-span-id=${parentSpanId} written to GITHUB_OUTPUT`);
-  }
+  if (isValidTraceId(traceId)) writeEnvLine(githubOutput, "trace-id", traceId, `trace-id=${traceId}`);
+  if (isValidSpanId(spanId)) writeEnvLine(githubOutput, "span-id", spanId, `span-id=${spanId}`);
+  if (isValidSpanId(parentSpanId)) writeEnvLine(githubOutput, "parent-span-id", parentSpanId, `parent-span-id=${parentSpanId}`);
 
   // Always propagate trace/span context to subsequent steps in this job so
   // that the conclusion span can find the same trace ID.
-  if (process.env.GITHUB_ENV) {
-    if (isValidTraceId(traceId)) {
-      appendFileSync(process.env.GITHUB_ENV, `GITHUB_AW_OTEL_TRACE_ID=${traceId}\n`);
-      console.log(`[otlp] GITHUB_AW_OTEL_TRACE_ID written to GITHUB_ENV`);
-    }
-    if (isValidSpanId(spanId)) {
-      appendFileSync(process.env.GITHUB_ENV, `GITHUB_AW_OTEL_PARENT_SPAN_ID=${spanId}\n`);
-      console.log(`[otlp] GITHUB_AW_OTEL_PARENT_SPAN_ID written to GITHUB_ENV`);
-    }
+  if (githubEnv) {
+    if (isValidTraceId(traceId)) writeEnvLine(githubEnv, "GITHUB_AW_OTEL_TRACE_ID", traceId, "GITHUB_AW_OTEL_TRACE_ID");
+    if (isValidSpanId(spanId)) writeEnvLine(githubEnv, "GITHUB_AW_OTEL_PARENT_SPAN_ID", spanId, "GITHUB_AW_OTEL_PARENT_SPAN_ID");
     // Propagate setup-end timestamp so the conclusion span can measure actual
     // job execution duration (setup-end → conclusion-start).
-    const setupEndMs = Math.floor(nowMs());
-    appendFileSync(process.env.GITHUB_ENV, `GITHUB_AW_OTEL_JOB_START_MS=${setupEndMs}\n`);
-    console.log(`[otlp] GITHUB_AW_OTEL_JOB_START_MS written to GITHUB_ENV`);
+    const setupEndMs = String(Math.floor(nowMs()));
+    writeEnvLine(githubEnv, "GITHUB_AW_OTEL_JOB_START_MS", setupEndMs, "GITHUB_AW_OTEL_JOB_START_MS");
   }
 }