diff --git a/scripts/build-manifest.mjs b/scripts/build-manifest.mjs
index b8f1602..f1bf775 100644
--- a/scripts/build-manifest.mjs
+++ b/scripts/build-manifest.mjs
@@ -31,6 +31,15 @@ const manifest = {
   configSchema: toolMetadata.configSchema,
   activation: toolMetadata.activation ?? { onStartup: true },
   channels: ["agentmail"],
+  // The Plugin Inspector emits a `channel-env-vars` deprecation warning whenever this field is
+  // present (it is unconditional — a setup entry does NOT suppress it). We keep it anyway: on our
+  // supported OpenClaw range (peerDependency floor >=2026.7.2-beta.3, currently the newest published
+  // release) `channelEnvVars` is still the only source OpenClaw reads to detect the channel as
+  // configured from AGENTMAIL_API_KEY in the environment (isStaticallyChannelConfigured) and to
+  // advertise expected env-shell keys. No setup-metadata replacement path has shipped in any release
+  // yet, so dropping this would regress env-driven setup with no upside.
+  // Remove this field (which clears the warning) only once our minimum supported OpenClaw version
+  // reads channel env names from the newer setup model instead — then also raise the floor to match.
   channelEnvVars: {
     agentmail: ["AGENTMAIL_API_KEY", "AGENTMAIL_WEBHOOK_SECRET"],
   },