diff --git a/pr-review/src/config.ts b/pr-review/src/config.ts
index 7237af6..466b7ad 100644
--- a/pr-review/src/config.ts
+++ b/pr-review/src/config.ts
@@ -17,7 +17,7 @@ if (process.env.NODE_ENV === "development") {
   // eslint-disable-next-line @typescript-eslint/no-for-in-array, no-restricted-syntax, guard-for-in
   for (const key in actionYaml.inputs) {
     const envKey = `INPUT_${key.toUpperCase()}`
-    const envValue = actionYaml.inputs[key].default
+    const envValue = actionYaml.inputs[key]?.default
     if (envValue && !Object.keys(process.env).includes(envKey)) {
       process.env[envKey] = envValue
     }
diff --git a/pr-review/src/hunk-reader.ts b/pr-review/src/hunk-reader.ts
index 683eaaa..1806efb 100644
--- a/pr-review/src/hunk-reader.ts
+++ b/pr-review/src/hunk-reader.ts
@@ -34,43 +34,50 @@ export function resolveHunkReferencesInComments(comments: AiReview["comments"],
       core.warning(`Could not find file for comment on ${comment.path}, start ${comment.start}, end ${comment.end}, ${comment.comment}, skipping.`)
     } else {
       const hunkChangeMap = currentFile.chunks.flatMap(hunk => hunk.changes.map(change => ({ change, hunk })))
-      let { change: startChange, hunk: startHunk } = hunkChangeMap[comment.start - 1] // eslint-disable-line prefer-const
-      let { change: endChange, hunk: endHunk } = hunkChangeMap[comment.end - 1] // eslint-disable-line prefer-const
+      const startEntry = hunkChangeMap[comment.start - 1]
+      const endEntry = hunkChangeMap[comment.end - 1]
 
-      if (!startHunk) {
-        core.warning(`Could not find hunk for comment on ${comment.path}, start ${comment.start}, end ${comment.end}, ${comment.comment}, skipping.`)
+      if (!startEntry || !endEntry) {
+        core.error(`Could not find hunk for comment on ${comment.path}, start ${comment.start}, end ${comment.end}, ${comment.comment}, skipping.`)
       } else {
-        if (startHunk !== endHunk) endChange = startHunk.changes.at(-1)!
+        const { change: startChange, hunk: startHunk } = startEntry
+        let { change: endChange, hunk: endHunk } = endEntry // eslint-disable-line prefer-const
 
-        const startSide = startChange.type !== "del" ? "RIGHT" : "LEFT"
-        const endSide = endChange.type !== "del" ? "RIGHT" : "LEFT"
+        if (!startHunk) {
+          core.warning(`Could not find hunk for comment on ${comment.path}, start ${comment.start}, end ${comment.end}, ${comment.comment}, skipping.`)
+        } else {
+          if (startHunk !== endHunk) endChange = startHunk.changes.at(-1)!
 
-        // get start line of the actual comment
-        let start: number
-        if (startChange.type === "normal") {
-          start = startChange.ln2
-        } else if (startChange.type === "add" || startChange.type === "del") {
-          start = startChange.ln
-        } else throw new Error(`Unknown change type.`)
+          const startSide = startChange.type !== "del" ? "RIGHT" : "LEFT"
+          const endSide = endChange.type !== "del" ? "RIGHT" : "LEFT"
 
-        // get end line of the actual comment
-        let end: number
-        if (endChange.type === "normal") {
-          end = endChange.ln2
-        } else if (endChange.type === "add" || endChange.type === "del") {
-          end = endChange.ln
-        } else throw new Error(`Unknown change type.`)
-        // make sure start and end are within the hunk
-        end = Math.min(end, endSide === "RIGHT" ? startHunk.newStart + startHunk.newLines - 1 : startHunk.oldStart + startHunk.oldLines - 1)
+          // get start line of the actual comment
+          let start: number
+          if (startChange.type === "normal") {
+            start = startChange.ln2
+          } else if (startChange.type === "add" || startChange.type === "del") {
+            start = startChange.ln
+          } else throw new Error(`Unknown change type.`)
 
-        result.push({
-          path: comment.path,
-          start_side: startSide !== endSide ? startSide : undefined, // only set start_side if it is a multi-line comment
-          side: startSide !== endSide ? endSide : startSide,
-          start_line: start !== end && start < end ? start : undefined, // only set start_line if it is a multi-line comment, start must be less than end
-          line: start !== end && start < end ? end : start,
-          body: comment.comment,
-        })
+          // get end line of the actual comment
+          let end: number
+          if (endChange.type === "normal") {
+            end = endChange.ln2
+          } else if (endChange.type === "add" || endChange.type === "del") {
+            end = endChange.ln
+          } else throw new Error(`Unknown change type.`)
+          // make sure start and end are within the hunk
+          end = Math.min(end, endSide === "RIGHT" ? startHunk.newStart + startHunk.newLines - 1 : startHunk.oldStart + startHunk.oldLines - 1)
+
+          result.push({
+            path: comment.path,
+            start_side: startSide !== endSide ? startSide : undefined, // only set start_side if it is a multi-line comment
+            side: startSide !== endSide ? endSide : startSide,
+            start_line: start !== end && start < end ? start : undefined, // only set start_line if it is a multi-line comment, start must be less than end
+            line: start !== end && start < end ? end : start,
+            body: comment.comment,
+          })
+        }
       }
     }
   })
diff --git a/pr-review/src/main.ts b/pr-review/src/main.ts
index 98486a8..9455f10 100644
--- a/pr-review/src/main.ts
+++ b/pr-review/src/main.ts
@@ -43,8 +43,8 @@ export async function run(config: Config): Promise<void> {
     const regex = new RegExp(`^${markerStart}\\s+<!-- (?<base>\\w+)\\.\\.\\.(?<head>\\w+) -->([\\s\\S]*?)${markerEnd}$`, "g")
     previousReviews.forEach(comment => {
       ;[...(comment.body?.matchAll(regex) ?? [])].forEach(match => {
-        const commentBase = match.groups!.base
-        const commentHead = match.groups!.head
+        const commentBase = match.groups!.base!
+        const commentHead = match.groups!.head!
         if (commentHead) base = commentHead !== head ? commentHead : commentBase
       })
     })
diff --git a/pr-review/tsconfig.json b/pr-review/tsconfig.json
index 2f26aac..87ed8f5 100644
--- a/pr-review/tsconfig.json
+++ b/pr-review/tsconfig.json
@@ -1,19 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/tsconfig",
+  "extends": "../tsconfig.json",
   "compilerOptions": {
-    "target": "ES2022",
-    "module": "NodeNext",
-    "rootDir": "./src",
-    "moduleResolution": "NodeNext",
-    "baseUrl": "./",
-    "sourceMap": true,
-    "outDir": "./dist",
-    "noImplicitAny": true,
-    "esModuleInterop": true,
-    "forceConsistentCasingInFileNames": true,
-    "strict": true,
-    "skipLibCheck": true,
-    "newLine": "lf"
-  },
-  "exclude": ["./dist", "./node_modules", "./__tests__", "./coverage"]
+    "rootDir": "./src"
+  }
 }
diff --git a/pr-summary/src/config.ts b/pr-summary/src/config.ts
index fe595cb..f71efcd 100644
--- a/pr-summary/src/config.ts
+++ b/pr-summary/src/config.ts
@@ -17,7 +17,7 @@ if (process.env.NODE_ENV === "development") {
   // eslint-disable-next-line @typescript-eslint/no-for-in-array, no-restricted-syntax, guard-for-in
   for (const key in actionYaml.inputs) {
     const envKey = `INPUT_${key.toUpperCase()}`
-    const envValue = actionYaml.inputs[key].default
+    const envValue = actionYaml.inputs[key]?.default
     if (envValue && !Object.keys(process.env).includes(envKey)) {
       process.env[envKey] = envValue
     }
diff --git a/pr-summary/src/main.ts b/pr-summary/src/main.ts
index efa92d1..13d9fa1 100644
--- a/pr-summary/src/main.ts
+++ b/pr-summary/src/main.ts
@@ -40,8 +40,8 @@ export async function run(config: Config): Promise<void> {
     const regex = new RegExp(`^${markerStart}\\s+<!-- (?<base>\\w+)\\.\\.\\.(?<head>\\w+) -->([\\s\\S]*?)${markerEnd}$`, "g")
     comments.forEach(comment => {
       ;[...(comment.body?.matchAll(regex) ?? [])].forEach(match => {
-        const commentBase = match.groups!.base
-        const commentHead = match.groups!.head
+        const commentBase = match.groups!.base!
+        const commentHead = match.groups!.head!
         if (commentHead) base = commentHead !== head ? commentHead : commentBase
       })
     })
diff --git a/pr-summary/tsconfig.json b/pr-summary/tsconfig.json
index 464cb8b..87ed8f5 100644
--- a/pr-summary/tsconfig.json
+++ b/pr-summary/tsconfig.json
@@ -1,19 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/tsconfig",
+  "extends": "../tsconfig.json",
   "compilerOptions": {
-    "target": "ES2022",
-    "module": "NodeNext",
-    "rootDir": "./src",
-    "moduleResolution": "NodeNext",
-    "baseUrl": "./",
-    "sourceMap": true,
-    "outDir": "./dist",
-    "noImplicitAny": true,
-    "esModuleInterop": true,
-    "forceConsistentCasingInFileNames": true,
-    "strict": true,
-    "skipLibCheck": true,
-    "newLine": "lf"
-  },
-  "exclude": ["./dist", "./node_modules"]
+    "rootDir": "./src"
+  }
 }
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..8443ea1
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,22 @@
+{
+  "$schema": "https://json.schemastore.org/tsconfig",
+  "compilerOptions": {
+    "composite": true,
+    "target": "esnext",
+    "module": "nodenext",
+    "moduleResolution": "nodenext",
+    "baseUrl": "./",
+    "sourceMap": true,
+    "outDir": "./dist",
+    "noImplicitAny": true,
+    "esModuleInterop": true,
+    "forceConsistentCasingInFileNames": true,
+    "noUncheckedIndexedAccess": true,
+    "strict": true,
+    "skipLibCheck": true,
+    "newLine": "lf",
+    "erasableSyntaxOnly": true,
+    "rewriteRelativeImportExtensions": true
+  },
+  "exclude": ["./dist", "./node_modules", "./__tests__", "./coverage"]
+}