diff --git a/plugins/kapso/skills/automate-whatsapp/SKILL.md b/plugins/kapso/skills/automate-whatsapp/SKILL.md
index b6a03e0..38427f0 100644
--- a/plugins/kapso/skills/automate-whatsapp/SKILL.md
+++ b/plugins/kapso/skills/automate-whatsapp/SKILL.md
@@ -159,6 +159,7 @@ Notes:
 - Non-decide nodes have 0 or 1 outgoing `next` edge
 - Decide edge labels must match `conditions[].label`
 - Edge keys are `source`/`target`/`label` (not `from`/`to`)
+- Agent nodes require `config.provider_model_id` — run `node scripts/list-provider-models.js` and set it (plus a non-empty `config.system_prompt`) before saving. `validate-graph.js` errors on a missing model id.
 
 For full schema details, see `references/graph-contract.md`.
 
diff --git a/plugins/kapso/skills/automate-whatsapp/references/node-types.md b/plugins/kapso/skills/automate-whatsapp/references/node-types.md
index 03bc183..defd51b 100644
--- a/plugins/kapso/skills/automate-whatsapp/references/node-types.md
+++ b/plugins/kapso/skills/automate-whatsapp/references/node-types.md
@@ -245,7 +245,8 @@ Use `automate-whatsapp` function scripts to find function IDs and update code.
 ```
 
 Notes:
-- `provider_model_id` is required. Use `scripts/list-provider-models.js` to find it.
+- `provider_model_id` is required. Run `node scripts/list-provider-models.js` to get a valid id and set it in `config.provider_model_id` **before** saving the node. `scripts/validate-graph.js` errors when an agent node is missing it, so validate the graph before `update-graph.js`.
+- `system_prompt` should be non-empty. `validate-graph.js` warns when it is blank.
 - Agent tool arrays live inside `data.config` (not at the `data` root).
 - `message_delivery_mode` controls user-visible text:
   - `auto_send_assistant_text` sends normal assistant text automatically.
diff --git a/plugins/kapso/skills/automate-whatsapp/scripts/validate-graph.js b/plugins/kapso/skills/automate-whatsapp/scripts/validate-graph.js
index 319cd06..197b119 100644
--- a/plugins/kapso/skills/automate-whatsapp/scripts/validate-graph.js
+++ b/plugins/kapso/skills/automate-whatsapp/scripts/validate-graph.js
@@ -80,7 +80,7 @@ function validateDefinition(definition) {
   }
 
   if (!nodes || !edges) {
-    return { errors, warnings, stats: { nodes: 0, edges: 0, decideNodes: 0 } };
+    return { errors, warnings, stats: { nodes: 0, edges: 0, decideNodes: 0, agentNodes: 0 } };
   }
 
   const nodeIds = new Set();
@@ -154,12 +154,30 @@ function validateDefinition(definition) {
   });
 
   let decideNodes = 0;
+  let agentNodes = 0;
   nodes.forEach((node) => {
     if (!node || typeof node !== 'object') return;
     const nodeId = node.id;
     const nodeType = nodeTypes[nodeId];
     const outgoing = outgoingEdges[nodeId] || [];
 
+    if (nodeType === 'agent') {
+      agentNodes += 1;
+      const config = (node.data || {}).config || {};
+
+      const providerModelId = config.provider_model_id;
+      if (typeof providerModelId !== 'string' || providerModelId.trim() === '') {
+        errors.push(
+          `agent node ${nodeId} is missing config.provider_model_id (required). Use scripts/list-provider-models.js to find a model id.`
+        );
+      }
+
+      const systemPrompt = config.system_prompt;
+      if (typeof systemPrompt !== 'string' || systemPrompt.trim() === '') {
+        warnings.push(`agent node ${nodeId} has an empty config.system_prompt`);
+      }
+    }
+
     if (nodeType === 'decide') {
       decideNodes += 1;
       const config = (node.data || {}).config || {};
@@ -207,7 +225,8 @@ function validateDefinition(definition) {
     stats: {
       nodes: nodes.length,
       edges: edges.length,
-      decideNodes
+      decideNodes,
+      agentNodes
     }
   };
 }