diff --git a/README.md b/README.md
index d9e4bd9ee7..6cebce4a4f 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 # GenAIScript
 
-Scripting environment with convenient tooling for file ingestion, prompt development and structured data extraction.
+JavaScript-ish environment with convenient tooling for file ingestion, prompt development and structured data extraction.
 
 ```js wrap
 // metadata and model configuration
diff --git a/packages/core/src/parameters.ts b/packages/core/src/parameters.ts
index 5d607786ad..11c60c96af 100644
--- a/packages/core/src/parameters.ts
+++ b/packages/core/src/parameters.ts
@@ -25,16 +25,17 @@ export function promptParameterTypeToJSONSchema(
         }
     else if (
         typeof t === "object" &&
-        ["number", "integer", "string", "object"].includes((t as any).type)
-    )
+        ["number", "integer", "string", "boolean", "object"].includes(
+            (t as any).type
+        )
+    ) {
         return <
             | JSONSchemaNumber
             | JSONSchemaString
             | JSONSchemaBoolean
             | JSONSchemaObject
         >t
-    // TODO better filtering
-    else if (typeof t === "object")
+    } else if (typeof t === "object")
         return <JSONSchemaObject>{
             type: "object",
             properties: Object.fromEntries(
diff --git a/packages/sample/genaisrc/parameters.genai.js b/packages/sample/genaisrc/parameters.genai.js
index 9bb067df36..f5efe20e52 100644
--- a/packages/sample/genaisrc/parameters.genai.js
+++ b/packages/sample/genaisrc/parameters.genai.js
@@ -35,6 +35,9 @@ script({
 console.log(`string: ${env.vars.string} ${typeof env.vars.string}`)
 console.log(`number: ${env.vars.number} ${typeof env.vars.number}`)
 console.log(`boolean: ${env.vars.boolean} ${typeof env.vars.boolean}`)
+console.log(`stringSchema: ${env.vars.stringSchema} ${typeof env.vars.stringSchema}`)
+console.log(`numberSchema: ${env.vars.numberSchema} ${typeof env.vars.numberSchema}`)
+console.log(`booleanSchema: ${env.vars.booleanSchema} ${typeof env.vars.booleanSchema}`)
 
 if (env.vars["string"] !== "abc") throw new Error("string parameter not set")
 if (env.vars["number"] !== 123) throw new Error("number parameter not set")
@@ -45,7 +48,3 @@ if (env.vars["numberSchema"] !== 456)
     throw new Error("numberSchema parameter not set")
 if (env.vars["booleanSchema"] !== true)
     throw new Error("booleanSchema parameter not set")
-
-// use $ to output formatted text to the prompt
-$`You are a helpful assistant.
-`
diff --git a/packages/sample/genaisrc/pr-create.genai.mts b/packages/sample/genaisrc/pr-create.genai.mts
new file mode 100644
index 0000000000..6f000d82de
--- /dev/null
+++ b/packages/sample/genaisrc/pr-create.genai.mts
@@ -0,0 +1,60 @@
+script({
+    model: "openai:gpt-4-32k",
+    files: [],
+    temperature: 1,
+    title: "pr-describe",
+    system: ["system", "system.fs_find_files", "system.fs_read_file"],
+})
+
+const defaultBranch = (env.vars.defaultBranch || "main") + ""
+const { text, finishReason, error } = await runPrompt(async (_) => {
+    const { stdout: changes } = await host.exec("git", [
+        "diff",
+        defaultBranch,
+        "--",
+        ".",
+        ":!**/genaiscript.d.ts",
+        ":!**/*sconfig.json",
+        ":!genaisrc/*",
+        ":!.github/*",
+        ":!.vscode/*",
+        ":!*yarn.lock",
+        ":!*THIRD_PARTY_LICENSES.md",
+    ])
+
+    _.def("GIT_DIFF", changes, {
+        language: "diff",
+        maxTokens: 20000,
+    })
+
+    _.$`You are an expert software developer and architect.
+
+## Task
+
+Create a pull request title and description for the changes in GIT_DIFF.
+
+The first line of the response should be the title of the pull request, the rest should be the description.
+
+   <title>
+   <description...>
+
+## Title Instructions
+
+- the title should be less than 50 characters
+
+## Description Instructions
+
+- do NOT explain that GIT_DIFF displays changes in the codebase
+- try to extract the intent of the changes, don't focus on the details
+- use bullet points to list the changes
+- use emojis to make the description more engaging
+- focus on the most important changes
+- ignore comments about imports (like added, remove, changed, etc.)
+- the public API is defined in "packages/core/src/prompt_template.d.ts" and "packages/core/src/prompt_type.ts".
+  Changes in those files are "user facing".
+`
+})
+
+// exec output
+console.log(error)
+console.log(text)
\ No newline at end of file
diff --git a/packages/sample/genaisrc/summarize-max-tokens.genai.js b/packages/sample/genaisrc/summarize-max-tokens.genai.js
index 68ccda106c..cedfed205a 100644
--- a/packages/sample/genaisrc/summarize-max-tokens.genai.js
+++ b/packages/sample/genaisrc/summarize-max-tokens.genai.js
@@ -1,12 +1,13 @@
 script({
     title: "summarize with max tokens",
     model: "openai:gpt-3.5-turbo",
+    files: ["src/rag/*"],
     tests: {
         files: ["src/rag/*"],
         keywords: ["markdown", "lorem", "microsoft"],
     },
 })
 
-def("FILE", env.files, { maxTokens: 20 })
+def("FILE", env.files, { maxTokens: 40 })
 
-$`Summarize each file. Be concise.`
+$`Extract keywords for the contents of FILE.`
diff --git a/packages/sample/genaisrc/summary-of-summary-phi3.genai.js b/packages/sample/genaisrc/summary-of-summary-phi3.genai.js
index c7a231226f..f91ddd107c 100644
--- a/packages/sample/genaisrc/summary-of-summary-phi3.genai.js
+++ b/packages/sample/genaisrc/summary-of-summary-phi3.genai.js
@@ -1,7 +1,7 @@
 script({
     model: "ollama:phi3",
     title: "summary of summary - phi3",
-    files: ["src/rag/*.md"], 
+    files: ["src/rag/*.md"],
     tests: {
         files: ["src/rag/*.md"],
         keywords: ["markdown", "lorem", "microsoft"],
@@ -13,11 +13,11 @@ for (const file of env.files) {
     const { text } = await runPrompt(
         (_) => {
             _.def("FILE", file)
-            _.$`Summarize the FILE and respond in plain text with one paragraph. Be consice. Ensure that summary is consistent with the content of FILE.`
+            _.$`Extract keywords for the contents of FILE.`
         },
         { model: "ollama:phi3", cacheName: "summary_phi3" }
     )
     def("FILE", { ...file, content: text })
 }
 // use summary
-$`Summarize FILE with short sentence.`
+$`Extract keywords for the contents of FILE.`