ci: add typechecking, fail fast in CI, and patch typechecking errors (#63)

src/agent/check-approval.ts

@@ -69,10 +69,12 @@ export async function getResumeData(
         const approvalMessage = matchingMessages.find(
           (msg) => msg.message_type === "approval_request_message",
         );
-        const inContextMessage =
-          approvalMessage ?? matchingMessages[matchingMessages.length - 1]!;
+        const lastMessage = matchingMessages[matchingMessages.length - 1];
+        const inContextMessage = approvalMessage ?? lastMessage;
 
-        messageToCheck = inContextMessage;
+        if (inContextMessage) {
+          messageToCheck = inContextMessage;
+        }
       } else {
         console.warn(
           `[check-approval] In-context message ${inContextLastMessageId} not found in cursor fetch.\n` +

src/agent/model.ts

@@ -25,7 +25,13 @@ export function resolveModel(modelIdentifier: string): string | null {
  */
 export function getDefaultModel(): string {
   const defaultModel = models.find((m) => m.isDefault);
-  return defaultModel?.handle || models[0].handle;
+  if (defaultModel) return defaultModel.handle;
+
+  const firstModel = models[0];
+  if (!firstModel) {
+    throw new Error("No models available in models.json");
+  }
+  return firstModel.handle;
 }
 
 /**

src/cli/components/AdvancedDiffRenderer.tsx

@@ -281,7 +281,9 @@ export function AdvancedDiffRenderer(
     let newNo = h.newStart;
     let lastRemovalNo: number | null = null;
     for (let i = 0; i < h.lines.length; i++) {
-      const raw = h.lines[i].raw || "";
+      const line = h.lines[i];
+      if (!line) continue;
+      const raw = line.raw || "";
       const ch = raw.charAt(0);
       const body = raw.slice(1);
       // Skip meta lines (e.g., "\ No newline at end of file"): do not display, do not advance counters,
@@ -291,7 +293,9 @@ export function AdvancedDiffRenderer(
       // Helper to find next non-meta '+' index
       const findNextPlus = (start: number): string | undefined => {
         for (let j = start + 1; j < h.lines.length; j++) {
-          const r = h.lines[j].raw || "";
+          const nextLine = h.lines[j];
+          if (!nextLine) continue;
+          const r = nextLine.raw || "";
           if (r.charAt(0) === "\\") continue; // skip meta
           if (r.startsWith("+")) return r.slice(1);
           break; // stop at first non-meta non-plus
@@ -301,7 +305,9 @@ export function AdvancedDiffRenderer(
       // Helper to find previous non-meta '-' index
       const findPrevMinus = (start: number): string | undefined => {
         for (let k = start - 1; k >= 0; k--) {
-          const r = h.lines[k].raw || "";
+          const prevLine = h.lines[k];
+          if (!prevLine) continue;
+          const r = prevLine.raw || "";
           if (r.charAt(0) === "\\") continue; // skip meta
           if (r.startsWith("-")) return r.slice(1);
           break; // stop at first non-meta non-minus

src/cli/components/MarkdownDisplay.tsx

@@ -77,7 +77,7 @@ export const MarkdownDisplay: React.FC<MarkdownDisplayProps> = ({
 
     // Check for headers
     const headerMatch = line.match(headerRegex);
-    if (headerMatch) {
+    if (headerMatch?.[1] && headerMatch[2] !== undefined) {
       const level = headerMatch[1].length;
       const content = headerMatch[2];
 
@@ -119,7 +119,12 @@ export const MarkdownDisplay: React.FC<MarkdownDisplayProps> = ({
 
     // Check for list items
     const listMatch = line.match(listItemRegex);
-    if (listMatch) {
+    if (
+      listMatch &&
+      listMatch[1] !== undefined &&
+      listMatch[2] &&
+      listMatch[3] !== undefined
+    ) {
       const indent = listMatch[1].length;
       const marker = listMatch[2];
       const content = listMatch[3];
@@ -146,7 +151,7 @@ export const MarkdownDisplay: React.FC<MarkdownDisplayProps> = ({
 
     // Check for blockquotes
     const blockquoteMatch = line.match(blockquoteRegex);
-    if (blockquoteMatch) {
+    if (blockquoteMatch && blockquoteMatch[1] !== undefined) {
       contentBlocks.push(
         <Box key={key} paddingLeft={2}>
           <Text dimColor>│ </Text>

src/cli/components/PasteAwareTextInput.tsx

@@ -60,6 +60,8 @@ export function PasteAwareTextInput({
     onSubmit?: (value: string) => void;
     placeholder?: string;
     focus?: boolean;
+    externalCursorOffset?: number;
+    onCursorOffsetChange?: (n: number) => void;
   }>;
 
   // Sync external value changes (treat incoming value as DISPLAY value)

src/cli/helpers/backfill.ts

@@ -123,6 +123,9 @@ export function backfillBuffers(
         if (toolCalls.length > 0 && toolCalls[0]?.tool_call_id) {
           const toolCall = toolCalls[0];
           const toolCallId = toolCall.tool_call_id;
+          // Skip if any required fields are missing
+          if (!toolCallId || !toolCall.name || !toolCall.arguments) break;
+
           const exists = buffers.byId.has(lineId);
 
           buffers.byId.set(lineId, {

src/cli/helpers/formatArgsDisplay.ts

@@ -23,11 +23,13 @@ export function formatArgsDisplay(argsJson: string): {
         if ("request_heartbeat" in clone) delete clone.request_heartbeat;
         parsed = clone;
         const keys = Object.keys(parsed);
+        const firstKey = keys[0];
         if (
           keys.length === 1 &&
-          ["query", "path", "file_path", "command", "label"].includes(keys[0])
+          firstKey &&
+          ["query", "path", "file_path", "command", "label"].includes(firstKey)
         ) {
-          const v = parsed[keys[0]];
+          const v = parsed[firstKey];
           display = typeof v === "string" ? v : String(v);
         } else {
           display = Object.entries(parsed)

src/cli/helpers/stream.ts

@@ -191,7 +191,7 @@ export async function drainStreamWithResume(
 
       // Use the resume result (should have proper stop_reason now)
       result = resumeResult;
-    } catch (e) {
+    } catch (_e) {
       // Resume failed - stick with the error stop_reason
       // The original error result will be returned
     }

src/permissions/analyzer.ts

@@ -161,7 +161,7 @@ function analyzeBashApproval(
   _workingDir: string,
 ): ApprovalContext {
   const parts = command.trim().split(/\s+/);
-  const baseCommand = parts[0];
+  const baseCommand = parts[0] || "";
   const firstArg = parts[1] || "";
 
   // Dangerous commands - no persistence
@@ -178,7 +178,7 @@ function analyzeBashApproval(
     "killall",
   ];
 
-  if (dangerousCommands.includes(baseCommand)) {
+  if (baseCommand && dangerousCommands.includes(baseCommand)) {
     return {
       recommendedRule: "",
       ruleDescription: "",
@@ -248,7 +248,7 @@ function analyzeBashApproval(
   }
 
   // Package manager commands
-  if (["npm", "bun", "yarn", "pnpm"].includes(baseCommand)) {
+  if (baseCommand && ["npm", "bun", "yarn", "pnpm"].includes(baseCommand)) {
     const subcommand = firstArg;
     const thirdPart = parts[2];
 
@@ -295,7 +295,7 @@ function analyzeBashApproval(
     "tail",
   ];
 
-  if (safeCommands.includes(baseCommand)) {
+  if (baseCommand && safeCommands.includes(baseCommand)) {
     return {
       recommendedRule: `Bash(${baseCommand}:*)`,
       ruleDescription: `'${baseCommand}' commands`,
@@ -318,7 +318,7 @@ function analyzeBashApproval(
 
     for (const segment of segments) {
       const segmentParts = segment.trim().split(/\s+/);
-      const segmentBase = segmentParts[0];
+      const segmentBase = segmentParts[0] || "";
       const segmentArg = segmentParts[1] || "";
 
       // Check if this segment is git command
@@ -350,7 +350,7 @@ function analyzeBashApproval(
       }
 
       // Check if this segment is npm/bun/yarn/pnpm
-      if (["npm", "bun", "yarn", "pnpm"].includes(segmentBase)) {
+      if (segmentBase && ["npm", "bun", "yarn", "pnpm"].includes(segmentBase)) {
         const subcommand = segmentArg;
         const thirdPart = segmentParts[2];
 

src/permissions/matcher.ts

@@ -26,7 +26,7 @@ export function matchesFilePattern(
   // Extract tool name and file path from query
   // Format: "ToolName(filePath)"
   const queryMatch = query.match(/^([^(]+)\((.+)\)$/);
-  if (!queryMatch) {
+  if (!queryMatch || !queryMatch[1] || !queryMatch[2]) {
     return false;
   }
   const queryTool = queryMatch[1];
@@ -35,7 +35,7 @@ export function matchesFilePattern(
   // Extract tool name and glob pattern from permission rule
   // Format: "ToolName(pattern)"
   const patternMatch = pattern.match(/^([^(]+)\((.+)\)$/);
-  if (!patternMatch) {
+  if (!patternMatch || !patternMatch[1] || !patternMatch[2]) {
     return false;
   }
   const patternTool = patternMatch[1];
@@ -98,7 +98,7 @@ export function matchesBashPattern(query: string, pattern: string): boolean {
   // Extract the command from query
   // Format: "Bash(actual command)" or "Bash()"
   const queryMatch = query.match(/^Bash\((.*)\)$/);
-  if (!queryMatch) {
+  if (!queryMatch || queryMatch[1] === undefined) {
     return false;
   }
   const command = queryMatch[1];
@@ -106,7 +106,7 @@ export function matchesBashPattern(query: string, pattern: string): boolean {
   // Extract the command pattern from permission rule
   // Format: "Bash(command pattern)" or "Bash()"
   const patternMatch = pattern.match(/^Bash\((.*)\)$/);
-  if (!patternMatch) {
+  if (!patternMatch || patternMatch[1] === undefined) {
     return false;
   }
   const commandPattern = patternMatch[1];

src/tests/clipboard.test.ts

@@ -76,7 +76,7 @@ test("buildMessageContentFromDisplay handles mixed content", () => {
     type: "text",
     text: "Start Pasted content middle ",
   });
-  expect(content[1].type).toBe("image");
+  expect(content[1]?.type).toBe("image");
   expect(content[2]).toEqual({ type: "text", text: " end" });
 });
 

src/tests/tools/bash-background.test.ts

@@ -11,8 +11,8 @@ describe("Bash background tools", () => {
       run_in_background: true,
     });
 
-    expect(result.content[0].text).toContain("background with ID:");
-    expect(result.content[0].text).toMatch(/bash_\d+/);
+    expect(result.content[0]?.text).toContain("background with ID:");
+    expect(result.content[0]?.text).toMatch(/bash_\d+/);
   });
 
   test("BashOutput retrieves output from background shell", async () => {
@@ -24,7 +24,7 @@ describe("Bash background tools", () => {
     });
 
     // Extract bash_id from the response text
-    const match = startResult.content[0].text.match(/bash_(\d+)/);
+    const match = startResult.content[0]?.text.match(/bash_(\d+)/);
     expect(match).toBeDefined();
     const bashId = `bash_${match?.[1]}`;
 
@@ -51,7 +51,7 @@ describe("Bash background tools", () => {
       run_in_background: true,
     });
 
-    const match = startResult.content[0].text.match(/bash_(\d+)/);
+    const match = startResult.content[0]?.text.match(/bash_(\d+)/);
     const bashId = `bash_${match?.[1]}`;
 
     // Kill it (KillBash uses shell_id parameter)

src/tests/tools/bash.test.ts

@@ -9,7 +9,7 @@ describe("Bash tool", () => {
     });
 
     expect(result.content).toBeDefined();
-    expect(result.content[0].text).toContain("Hello, World!");
+    expect(result.content[0]?.text).toContain("Hello, World!");
     expect(result.isError).toBeUndefined();
   });
 
@@ -19,7 +19,7 @@ describe("Bash tool", () => {
       description: "Test stderr",
     });
 
-    expect(result.content[0].text).toContain("error message");
+    expect(result.content[0]?.text).toContain("error message");
   });
 
   test("returns error for failed command", async () => {
@@ -29,7 +29,7 @@ describe("Bash tool", () => {
     });
 
     expect(result.isError).toBe(true);
-    expect(result.content[0].text).toContain("Exit code");
+    expect(result.content[0]?.text).toContain("Exit code");
   });
 
   test("times out long-running command", async () => {
@@ -40,7 +40,7 @@ describe("Bash tool", () => {
     });
 
     expect(result.isError).toBe(true);
-    expect(result.content[0].text).toContain("timed out");
+    expect(result.content[0]?.text).toContain("timed out");
   }, 2000);
 
   test("runs command in background mode", async () => {
@@ -50,8 +50,8 @@ describe("Bash tool", () => {
       run_in_background: true,
     });
 
-    expect(result.content[0].text).toContain("background with ID:");
-    expect(result.content[0].text).toMatch(/bash_\d+/);
+    expect(result.content[0]?.text).toContain("background with ID:");
+    expect(result.content[0]?.text).toMatch(/bash_\d+/);
   });
 
   test("handles complex commands with pipes", async () => {
@@ -65,8 +65,8 @@ describe("Bash tool", () => {
       description: "Test pipe",
     });
 
-    expect(result.content[0].text).toContain("bar");
-    expect(result.content[0].text).not.toContain("foo");
+    expect(result.content[0]?.text).toContain("bar");
+    expect(result.content[0]?.text).not.toContain("foo");
   });
 
   test("lists background processes with /bashes command", async () => {
@@ -76,7 +76,7 @@ describe("Bash tool", () => {
     });
 
     expect(result.content).toBeDefined();
-    expect(result.content[0].text).toBeDefined();
+    expect(result.content[0]?.text).toBeDefined();
   });
 
   test("throws error when command is missing", async () => {

src/tests/tools/edit.test.ts

@@ -108,7 +108,7 @@ describe("Edit tool", () => {
         file_path: file,
         old_string: "World",
         new_str: "Bun",
-      } as Parameters<typeof edit>[0]),
+      } as unknown as Parameters<typeof edit>[0]),
     ).rejects.toThrow(/missing required parameter.*new_string/);
   });
 });

src/tests/tools/ls.test.ts

@@ -17,9 +17,9 @@ describe("LS tool", () => {
 
     const result = await ls({ path: testDir.path });
 
-    expect(result.content[0].text).toContain("file1.txt");
-    expect(result.content[0].text).toContain("file2.txt");
-    expect(result.content[0].text).toContain("subdir/");
+    expect(result.content[0]?.text).toContain("file1.txt");
+    expect(result.content[0]?.text).toContain("file2.txt");
+    expect(result.content[0]?.text).toContain("subdir/");
   });
 
   test("shows directories with trailing slash", async () => {
@@ -29,8 +29,8 @@ describe("LS tool", () => {
 
     const result = await ls({ path: testDir.path });
 
-    expect(result.content[0].text).toContain("folder/");
-    expect(result.content[0].text).toContain("file.txt");
+    expect(result.content[0]?.text).toContain("folder/");
+    expect(result.content[0]?.text).toContain("file.txt");
   });
 
   test("throws error for non-existent directory", async () => {
@@ -64,10 +64,10 @@ describe("LS tool", () => {
       ignore: ["*.log", "node_modules"],
     });
 
-    expect(result.content[0].text).toContain("file1.txt");
-    expect(result.content[0].text).toContain("important.txt");
-    expect(result.content[0].text).not.toContain("file2.log");
-    expect(result.content[0].text).not.toContain("node_modules");
+    expect(result.content[0]?.text).toContain("file1.txt");
+    expect(result.content[0]?.text).toContain("important.txt");
+    expect(result.content[0]?.text).not.toContain("file2.log");
+    expect(result.content[0]?.text).not.toContain("node_modules");
   });
 
   test("throws error when ignore is a string instead of array", async () => {

src/tests/tools/multiedit.test.ts

@@ -96,7 +96,7 @@ describe("MultiEdit tool", () => {
       multi_edit({
         file_path: file,
         edits: [
-          { old_string: "foo", new_str: "baz" } as Parameters<
+          { old_string: "foo", new_str: "baz" } as unknown as Parameters<
             typeof multi_edit
           >[0]["edits"][0],
         ],

src/tests/tools/tool-truncation.test.ts

@@ -267,6 +267,7 @@ describe("tool truncation integration tests", () => {
         const bashIdMatch = message.match(/with ID: (.+)/);
         expect(bashIdMatch).toBeTruthy();
         const bashId = bashIdMatch?.[1];
+        if (!bashId) throw new Error("bashId not found");
 
         // Wait a bit for output to accumulate
         await new Promise((resolve) => setTimeout(resolve, 100));

src/tools/impl/Grep.ts

@@ -113,7 +113,9 @@ export async function grep(args: GrepArgs): Promise<GrepResult> {
       for (const line of lines) {
         const parts = line.split(":");
         if (parts.length >= 2) {
-          const count = parseInt(parts[parts.length - 1], 10);
+          const lastPart = parts[parts.length - 1];
+          if (!lastPart) continue;
+          const count = parseInt(lastPart, 10);
           if (!Number.isNaN(count) && count > 0) {
             totalMatches += count;
             filesWithMatches++;

src/tools/impl/LS.ts

@@ -19,7 +19,11 @@ export async function ls(
   args: LSArgs,
 ): Promise<{ content: Array<{ type: string; text: string }> }> {
   validateRequiredParams(args, ["path"], "LS");
-  validateParamTypes(args, LSSchema, "LS");
+  validateParamTypes(
+    args as unknown as Record<string, unknown>,
+    LSSchema,
+    "LS",
+  );
   const { path: inputPath, ignore = [] } = args;
   const dirPath = resolve(inputPath);
   try {

src/tools/impl/MultiEdit.ts

@@ -25,12 +25,16 @@ export async function multi_edit(
     throw new Error(`File path must be absolute, got: ${file_path}`);
   if (!edits || edits.length === 0) throw new Error("No edits provided");
   for (let i = 0; i < edits.length; i++) {
+    const edit = edits[i];
+    if (!edit) {
+      throw new Error(`Edit ${i + 1} is undefined`);
+    }
     validateRequiredParams(
-      edits[i] as Record<string, unknown>,
+      edit as unknown as Record<string, unknown>,
       ["old_string", "new_string"],
       `MultiEdit (edit ${i + 1})`,
     );
-    if (edits[i].old_string === edits[i].new_string)
+    if (edit.old_string === edit.new_string)
       throw new Error(
         `Edit ${i + 1}: No changes to make: old_string and new_string are exactly the same.`,
       );
@@ -39,7 +43,9 @@ export async function multi_edit(
     let content = await fs.readFile(file_path, "utf-8");
     const appliedEdits: string[] = [];
     for (let i = 0; i < edits.length; i++) {
-      const { old_string, new_string, replace_all = false } = edits[i];
+      const edit = edits[i];
+      if (!edit) continue;
+      const { old_string, new_string, replace_all = false } = edit;
       const occurrences = content.split(old_string).length - 1;
       if (occurrences === 0) {
         throw new Error(

src/tools/toolDefinitions.ts

@@ -35,7 +35,7 @@ import ReadSchema from "./schemas/Read.json";
 import TodoWriteSchema from "./schemas/TodoWrite.json";
 import WriteSchema from "./schemas/Write.json";
 
-type ToolImplementation = (args: Record<string, any>) => Promise<any>;
+type ToolImplementation = (args: Record<string, unknown>) => Promise<unknown>;
 
 interface ToolAssets {
   schema: Record<string, unknown>;
@@ -47,62 +47,62 @@ const toolDefinitions = {
   Bash: {
     schema: BashSchema,
     description: BashDescription.trim(),
-    impl: bash as ToolImplementation,
+    impl: bash as unknown as ToolImplementation,
   },
   BashOutput: {
     schema: BashOutputSchema,
     description: BashOutputDescription.trim(),
-    impl: bash_output as ToolImplementation,
+    impl: bash_output as unknown as ToolImplementation,
   },
   Edit: {
     schema: EditSchema,
     description: EditDescription.trim(),
-    impl: edit as ToolImplementation,
+    impl: edit as unknown as ToolImplementation,
   },
   ExitPlanMode: {
     schema: ExitPlanModeSchema,
     description: ExitPlanModeDescription.trim(),
-    impl: exit_plan_mode as ToolImplementation,
+    impl: exit_plan_mode as unknown as ToolImplementation,
   },
   Glob: {
     schema: GlobSchema,
     description: GlobDescription.trim(),
-    impl: glob as ToolImplementation,
+    impl: glob as unknown as ToolImplementation,
   },
   Grep: {
     schema: GrepSchema,
     description: GrepDescription.trim(),
-    impl: grep as ToolImplementation,
+    impl: grep as unknown as ToolImplementation,
   },
   KillBash: {
     schema: KillBashSchema,
     description: KillBashDescription.trim(),
-    impl: kill_bash as ToolImplementation,
+    impl: kill_bash as unknown as ToolImplementation,
   },
   LS: {
     schema: LSSchema,
     description: LSDescription.trim(),
-    impl: ls as ToolImplementation,
+    impl: ls as unknown as ToolImplementation,
   },
   MultiEdit: {
     schema: MultiEditSchema,
     description: MultiEditDescription.trim(),
-    impl: multi_edit as ToolImplementation,
+    impl: multi_edit as unknown as ToolImplementation,
   },
   Read: {
     schema: ReadSchema,
     description: ReadDescription.trim(),
-    impl: read as ToolImplementation,
+    impl: read as unknown as ToolImplementation,
   },
   TodoWrite: {
     schema: TodoWriteSchema,
     description: TodoWriteDescription.trim(),
-    impl: todo_write as ToolImplementation,
+    impl: todo_write as unknown as ToolImplementation,
   },
   Write: {
     schema: WriteSchema,
     description: WriteDescription.trim(),
-    impl: write as ToolImplementation,
+    impl: write as unknown as ToolImplementation,
   },
 } as const satisfies Record<string, ToolAssets>;