use yaml to render chat messages in trace

packages/core/src/chat.ts

@@ -480,8 +480,8 @@ export async function executeChatSession(
 
         let genVars: Record<string, string>
         while (true) {
+            trace.detailsFenced(`💬 messages`, messages, "yaml")
             trace.startDetails(`📤 llm request (${messages.length} messages)`)
-            trace.detailsFenced(`💬 messages`, messages, "json")
             let resp: ChatCompletionResponse
             try {
                 checkCancelled(cancellationToken)

packages/sample/genaisrc/injection.genai.js

@@ -1,9 +1,13 @@
 script({
     system: [],
+    files: "src/xpai/write-a-poem.txt",
 })
 
-const file = await workspace.readText("src/xpai/write-a-poem.txt")
+const file = env.files[0]
 
 $`Translate the following text from English to French:
 
-> ${file.content}`
+\`\`\`
+${file.content}
+\`\`\`
+`

packages/sample/genaisrc/translate.genai.js

@@ -9,14 +9,14 @@ const lang = env.vars.lang || "French"
 
 for (const file of env.files) {
     const canary = Math.random().toString(36).substring(7)
-    const res = await runPrompt((_) => {
-        _.$`Respond with ${canary}.`
-        _.def("FILE", file)
-    })
-    console.log(res.text)
-    if (res.text !== canary) {
-        cancel("file contains adverse content")
-    }
+    const res = await runPrompt(
+        (_) => {
+            _.$`Respond with ${canary}.`
+            _.def("FILE", file)
+        },
+        { label: file.filename }
+    )
+    if (res.text !== canary) cancel("file contains adverse content")
 }
 
 def("FILE", env.files)