diff --git a/package.json b/package.json
index 7356ac65..5ec80e1b 100644
--- a/package.json
+++ b/package.json
@@ -25,6 +25,7 @@
   "dependencies": {
     "@dqbd/tiktoken": "^1.0.7",
     "dotenv-safe": "^8.2.0",
+    "jsonrepair": "^3.1.0",
     "mustache": "^4.2.0",
     "openai-fetch": "^1.2.1",
     "p-map": "^6.0.0",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index f422f76d..9a0d8d7e 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -7,6 +7,9 @@ dependencies:
   dotenv-safe:
     specifier: ^8.2.0
     version: 8.2.0
+  jsonrepair:
+    specifier: ^3.1.0
+    version: 3.1.0
   mustache:
     specifier: ^4.2.0
     version: 4.2.0
@@ -1461,6 +1464,11 @@ packages:
     engines: {node: ^14.17.0 || ^16.13.0 || >=18.0.0}
     dev: false
 
+  /jsonrepair@3.1.0:
+    resolution: {integrity: sha512-idqReg23J0PVRAADmZMc5xQM3xeOX5bTB6OTyMnzq33IXJXmn9iJuWIEvGmrN80rQf4d7uLTMEDwpzujNcI0Rg==}
+    hasBin: true
+    dev: false
+
   /kind-of@6.0.3:
     resolution: {integrity: sha512-dcS1ul+9tmeD95T+x28/ehLgd9mENa3LsvDTtzm3vyBEO7RPptvAD+t44WVXaUjTBRcrpFeFlC8WCruUR456hw==}
     engines: {node: '>=0.10.0'}
diff --git a/src/llm.ts b/src/llm.ts
index bc6d13ba..eeb7baea 100644
--- a/src/llm.ts
+++ b/src/llm.ts
@@ -1,3 +1,4 @@
+import { jsonrepair } from 'jsonrepair'
 import Mustache from 'mustache'
 import { dedent } from 'ts-dedent'
 import type { SetRequired } from 'type-fest'
@@ -5,6 +6,10 @@ import { ZodRawShape, ZodTypeAny, z } from 'zod'
 import { printNode, zodToTs } from 'zod-to-ts'
 
 import * as types from './types'
+import {
+  extractJSONArrayFromString,
+  extractJSONObjectFromString
+} from './utils'
 
 const defaultOpenAIModel = 'gpt-3.5-turbo'
 
@@ -174,6 +179,8 @@ export class OpenAIChatModelBuilder<
       input = inputSchema.parse(input)
     }
 
+    // TODO: validate input message variables against input schema
+
     const messages = this._messages
       .map((message) => {
         return {
@@ -185,6 +192,24 @@ export class OpenAIChatModelBuilder<
       })
       .filter((message) => message.content)
 
+    if (this._options.output) {
+      const outputSchema =
+        this._options.output instanceof z.ZodType
+          ? this._options.output
+          : z.object(this._options.output)
+
+      const { node } = zodToTs(outputSchema)
+      const tsTypeString = printNode(node)
+
+      messages.push({
+        role: 'system',
+        content: dedent`Output JSON only in the following format:
+          \`\`\`ts
+          ${tsTypeString}
+          \`\`\``
+      })
+    }
+
     // TODO: filter/compress messages based on token counts
 
     const completion = await this._client.createChatCompletion({
@@ -199,10 +224,28 @@ export class OpenAIChatModelBuilder<
           ? this._options.output
           : z.object(this._options.output)
 
-      // TODO: convert string => object if necessary
+      let output: any = completion.message.content
+      if (outputSchema instanceof z.ZodArray) {
+        try {
+          const trimmedOutput = extractJSONArrayFromString(output)
+          output = jsonrepair(trimmedOutput ?? output)
+        } catch (err) {
+          // TODO
+          throw err
+        }
+      } else if (outputSchema instanceof z.ZodObject) {
+        try {
+          const trimmedOutput = extractJSONObjectFromString(output)
+          output = jsonrepair(trimmedOutput ?? output)
+        } catch (err) {
+          // TODO
+          throw err
+        }
+      }
+
       // TODO: handle errors, retry logic, and self-healing
 
-      return outputSchema.parse(completion.message.content)
+      return outputSchema.parse(output)
     } else {
       return completion.message.content as any
     }
diff --git a/src/temp.ts b/src/temp.ts
index 53ce2477..4e257fae 100644
--- a/src/temp.ts
+++ b/src/temp.ts
@@ -12,28 +12,26 @@ async function main() {
   const openai = new OpenAIClient({ apiKey: process.env.OPENAI_API_KEY! })
   const $ = new Agentic({ openai })
 
-  const ex0 = await $.gpt4(`give me a single boolean value`)
-    .output(z.boolean())
-    // .retry({ attempts: 3 })
-    .call()
-
-  console.log(ex0)
+  // const ex0 = await $.gpt4(`give me a single boolean value`)
+  //   .output(z.boolean())
+  //   // .retry({ attempts: 3 })
+  //   .call()
+  // console.log(ex0)
 
   const ex1 = await $.gpt4(`give me fake data conforming to this schema`)
     .output(z.object({ foo: z.string(), bar: z.number() }))
     // .retry({ attempts: 3 })
     .call()
-
-  const getBoolean = $.gpt4(`give me a single boolean value {{foo}}`)
-    .input(z.object({ foo: z.string() }))
-    .output(z.boolean())
-
-  await Promise.all([
-    getBoolean.call({ foo: 'foo' }),
-    getBoolean.call({ foo: 'bar' })
-  ])
-
   console.log(ex1)
+
+  // const getBoolean = $.gpt4(`give me a single boolean value {{foo}}`)
+  //   .input(z.object({ foo: z.string() }))
+  //   .output(z.boolean())
+
+  // await Promise.all([
+  //   getBoolean.call({ foo: 'foo' }),
+  //   getBoolean.call({ foo: 'bar' })
+  // ])
 }
 
 main()
diff --git a/src/utils.ts b/src/utils.ts
new file mode 100644
index 00000000..d407dfe5
--- /dev/null
+++ b/src/utils.ts
@@ -0,0 +1,5 @@
+export const extractJSONObjectFromString = (text: string): string | undefined =>
+  text.match(/\{(.|\n)*\}/gm)?.[0]
+
+export const extractJSONArrayFromString = (text: string): string | undefined =>
+  text.match(/\[(.|\n)*\]/gm)?.[0]