feat: add CoStrict AI assistant support

README.md

@@ -92,6 +92,7 @@ These tools have built-in OpenSpec commands. Select the OpenSpec integration whe
 |------|----------|
 | **Claude Code** | `/openspec:proposal`, `/openspec:apply`, `/openspec:archive` |
 | **CodeBuddy Code (CLI)** | `/openspec:proposal`, `/openspec:apply`, `/openspec:archive` (`.codebuddy/commands/`) — see [docs](https://www.codebuddy.ai/cli) |
+| **Costrict** | `/openspec-proposal`, `/openspec-apply`, `/openspec-archive` (`.cospec/openspec/commands/`) — see [docs](https://costrict.ai)|
 | **Cursor** | `/openspec-proposal`, `/openspec-apply`, `/openspec-archive` |
 | **Cline** | Rules in `.clinerules/` directory (`.clinerules/openspec-*.md`) |
 | **Crush** | `/openspec-proposal`, `/openspec-apply`, `/openspec-archive` (`.crush/commands/openspec/`) |

src/core/config.ts

@@ -21,6 +21,7 @@ export const AI_TOOLS: AIToolOption[] = [
   { name: 'Claude Code', value: 'claude', available: true, successLabel: 'Claude Code' },
   { name: 'Cline', value: 'cline', available: true, successLabel: 'Cline' },
   { name: 'CodeBuddy Code (CLI)', value: 'codebuddy', available: true, successLabel: 'CodeBuddy Code' },
+  { name: 'Costrict', value: 'costrict', available: true, successLabel: 'Costrict' },
   { name: 'Crush', value: 'crush', available: true, successLabel: 'Crush' },
   { name: 'Cursor', value: 'cursor', available: true, successLabel: 'Cursor' },
   { name: 'Factory Droid', value: 'factory', available: true, successLabel: 'Factory Droid' },

src/core/configurators/costrict.ts

@@ -0,0 +1,23 @@
+import path from 'path';
+import { ToolConfigurator } from './base.js';
+import { FileSystemUtils } from '../../utils/file-system.js';
+import { TemplateManager } from '../templates/index.js';
+import { OPENSPEC_MARKERS } from '../config.js';
+
+export class CostrictConfigurator implements ToolConfigurator {
+  name = 'Costrict';
+  configFileName = 'COSTRICT.md';
+  isAvailable = true;
+
+  async configure(projectPath: string, openspecDir: string): Promise<void> {
+    const filePath = path.join(projectPath, this.configFileName);
+    const content = TemplateManager.getCostrictTemplate();
+
+    await FileSystemUtils.updateFileWithMarkers(
+      filePath,
+      content,
+      OPENSPEC_MARKERS.start,
+      OPENSPEC_MARKERS.end
+    );
+  }
+}

src/core/configurators/registry.ts

@@ -2,6 +2,7 @@ import { ToolConfigurator } from './base.js';
 import { ClaudeConfigurator } from './claude.js';
 import { ClineConfigurator } from './cline.js';
 import { CodeBuddyConfigurator } from './codebuddy.js';
+import { CostrictConfigurator } from './costrict.js';
 import { AgentsStandardConfigurator } from './agents.js';
 
 export class ToolRegistry {
@@ -11,11 +12,13 @@ export class ToolRegistry {
     const claudeConfigurator = new ClaudeConfigurator();
     const clineConfigurator = new ClineConfigurator();
     const codeBuddyConfigurator = new CodeBuddyConfigurator();
+    const costrictConfigurator = new CostrictConfigurator();
     const agentsConfigurator = new AgentsStandardConfigurator();
     // Register with the ID that matches the checkbox value
     this.tools.set('claude', claudeConfigurator);
     this.tools.set('cline', clineConfigurator);
     this.tools.set('codebuddy', codeBuddyConfigurator);
+    this.tools.set('costrict', costrictConfigurator);
     this.tools.set('agents', agentsConfigurator);
   }
 

src/core/configurators/slash/costrict.ts

@@ -0,0 +1,36 @@
+import { SlashCommandConfigurator } from './base.js';
+import { SlashCommandId } from '../../templates/index.js';
+
+const FILE_PATHS: Record<SlashCommandId, string> = {
+  proposal: '.cospec/openspec/commands/openspec-proposal.md',
+  apply: '.cospec/openspec/commands/openspec-apply.md',
+  archive: '.cospec/openspec/commands/openspec-archive.md'
+};
+
+const FRONTMATTER: Record<SlashCommandId, string> = {
+  proposal: `---
+description: "Scaffold a new OpenSpec change and validate strictly."
+argument-hint: feature description or request
+---`,
+  apply: `---
+description: "Implement an approved OpenSpec change and keep tasks in sync."
+argument-hint: change-id
+---`,
+  archive: `---
+description: "Archive a deployed OpenSpec change and update specs."
+argument-hint: change-id
+---`
+};
+
+export class CostrictSlashCommandConfigurator extends SlashCommandConfigurator {
+  readonly toolId = 'costrict';
+  readonly isAvailable = true;
+
+  protected getRelativePath(id: SlashCommandId): string {
+    return FILE_PATHS[id];
+  }
+
+  protected getFrontmatter(id: SlashCommandId): string | undefined {
+    return FRONTMATTER[id];
+  }
+}

src/core/configurators/slash/registry.ts

@@ -12,6 +12,7 @@ import { FactorySlashCommandConfigurator } from './factory.js';
 import { AuggieSlashCommandConfigurator } from './auggie.js';
 import { ClineSlashCommandConfigurator } from './cline.js';
 import { CrushSlashCommandConfigurator } from './crush.js';
+import { CostrictSlashCommandConfigurator } from './costrict.js';
 
 export class SlashCommandRegistry {
   private static configurators: Map<string, SlashCommandConfigurator> = new Map();
@@ -30,6 +31,7 @@ export class SlashCommandRegistry {
     const auggie = new AuggieSlashCommandConfigurator();
     const cline = new ClineSlashCommandConfigurator();
     const crush = new CrushSlashCommandConfigurator();
+    const costrict = new CostrictSlashCommandConfigurator();
 
     this.configurators.set(claude.toolId, claude);
     this.configurators.set(codeBuddy.toolId, codeBuddy);
@@ -44,6 +46,7 @@ export class SlashCommandRegistry {
     this.configurators.set(auggie.toolId, auggie);
     this.configurators.set(cline.toolId, cline);
     this.configurators.set(crush.toolId, crush);
+    this.configurators.set(costrict.toolId, costrict);
   }
 
   static register(configurator: SlashCommandConfigurator): void {

src/core/templates/costrict-template.ts

@@ -0,0 +1 @@
+export { agentsRootStubTemplate as costrictTemplate } from './agents-root-stub.js';

src/core/templates/index.ts

@@ -2,6 +2,7 @@ import { agentsTemplate } from './agents-template.js';
 import { projectTemplate, ProjectContext } from './project-template.js';
 import { claudeTemplate } from './claude-template.js';
 import { clineTemplate } from './cline-template.js';
+import { costrictTemplate } from './costrict-template.js';
 import { agentsRootStubTemplate } from './agents-root-stub.js';
 import { getSlashCommandBody, SlashCommandId } from './slash-command-templates.js';
 
@@ -32,6 +33,10 @@ export class TemplateManager {
     return clineTemplate;
   }
 
+  static getCostrictTemplate(): string {
+    return costrictTemplate;
+  }
+
   static getAgentsStandardTemplate(): string {
     return agentsRootStubTemplate;
   }

test/core/init.test.ts

@@ -995,6 +995,93 @@ describe('InitCommand', () => {
       );
       expect(crushChoice.configured).toBe(true);
     });
+
+    it('should create Costrict slash command files with templates', async () => {
+      queueSelections('costrict', DONE);
+
+      await initCommand.execute(testDir);
+
+      const costrictProposal = path.join(
+        testDir,
+        '.cospec/openspec/commands/openspec-proposal.md'
+      );
+      const costrictApply = path.join(
+        testDir,
+        '.cospec/openspec/commands/openspec-apply.md'
+      );
+      const costrictArchive = path.join(
+        testDir,
+        '.cospec/openspec/commands/openspec-archive.md'
+      );
+
+      expect(await fileExists(costrictProposal)).toBe(true);
+      expect(await fileExists(costrictApply)).toBe(true);
+      expect(await fileExists(costrictArchive)).toBe(true);
+
+      const proposalContent = await fs.readFile(costrictProposal, 'utf-8');
+      expect(proposalContent).toContain('---');
+      expect(proposalContent).toContain('description: "Scaffold a new OpenSpec change and validate strictly."');
+      expect(proposalContent).toContain('argument-hint: feature description or request');
+      expect(proposalContent).toContain('<!-- OPENSPEC:START -->');
+      expect(proposalContent).toContain('**Guardrails**');
+
+      const applyContent = await fs.readFile(costrictApply, 'utf-8');
+      expect(applyContent).toContain('---');
+      expect(applyContent).toContain('description: "Implement an approved OpenSpec change and keep tasks in sync."');
+      expect(applyContent).toContain('argument-hint: change-id');
+      expect(applyContent).toContain('Work through tasks sequentially');
+
+      const archiveContent = await fs.readFile(costrictArchive, 'utf-8');
+      expect(archiveContent).toContain('---');
+      expect(archiveContent).toContain('description: "Archive a deployed OpenSpec change and update specs."');
+      expect(archiveContent).toContain('argument-hint: change-id');
+      expect(archiveContent).toContain('openspec archive <id> --yes');
+    });
+
+    it('should mark Costrict as already configured during extend mode', async () => {
+      queueSelections('costrict', DONE, 'costrict', DONE);
+      await initCommand.execute(testDir);
+      await initCommand.execute(testDir);
+
+      const secondRunArgs = mockPrompt.mock.calls[1][0];
+      const costrictChoice = secondRunArgs.choices.find(
+        (choice: any) => choice.value === 'costrict'
+      );
+      expect(costrictChoice.configured).toBe(true);
+    });
+
+    it('should create COSTRICT.md when Costrict is selected', async () => {
+      queueSelections('costrict', DONE);
+
+      await initCommand.execute(testDir);
+
+      const costrictPath = path.join(testDir, 'COSTRICT.md');
+      expect(await fileExists(costrictPath)).toBe(true);
+
+      const content = await fs.readFile(costrictPath, 'utf-8');
+      expect(content).toContain('<!-- OPENSPEC:START -->');
+      expect(content).toContain("@/openspec/AGENTS.md");
+      expect(content).toContain('openspec update');
+      expect(content).toContain('<!-- OPENSPEC:END -->');
+    });
+
+    it('should update existing COSTRICT.md with markers', async () => {
+      queueSelections('costrict', DONE);
+
+      const costrictPath = path.join(testDir, 'COSTRICT.md');
+      const existingContent =
+        '# My Costrict Instructions\nCustom instructions here';
+      await fs.writeFile(costrictPath, existingContent);
+
+      await initCommand.execute(testDir);
+
+      const updatedContent = await fs.readFile(costrictPath, 'utf-8');
+      expect(updatedContent).toContain('<!-- OPENSPEC:START -->');
+      expect(updatedContent).toContain("@/openspec/AGENTS.md");
+      expect(updatedContent).toContain('openspec update');
+      expect(updatedContent).toContain('<!-- OPENSPEC:END -->');
+      expect(updatedContent).toContain('Custom instructions here');
+    });
   });
 
   describe('non-interactive mode', () => {