Support prompt variants

packages/ai-chat/src/common/universal-chat-agent.ts

@@ -76,6 +76,12 @@ simple solutions.
 `
 };
 
+export const universalTemplateVariant: PromptTemplate = {
+   id: 'universal-system-empty',
+   template: '',
+   variantOf: universalTemplate.id,
+};
+
 @injectable()
 export class UniversalChatAgent extends AbstractStreamParsingChatAgent implements ChatAgent {
    name: string;
@@ -96,7 +102,7 @@ export class UniversalChatAgent extends AbstractStreamParsingChatAgent implement
          + 'questions the user might ask. The universal agent currently does not have any context by default, i.e. it cannot '
          + 'access the current user context or the workspace.';
       this.variables = [];
-      this.promptTemplates = [universalTemplate];
+      this.promptTemplates = [universalTemplate, universalTemplateVariant];
       this.functions = [];
       this.agentSpecificVariables = [];
    }

packages/ai-core/src/browser/ai-configuration/agent-configuration-widget.tsx

@@ -137,14 +137,26 @@ export class AIAgentConfigurationWidget extends ReactWidget {
                     Enable Agent
                 </label>
             </div>
+            <div className="settings-section-subcategory-title ai-settings-section-subcategory-title">
+                Prompt Templates
+            </div>
             <div className='ai-templates'>
-                {agent.promptTemplates?.map(template =>
-                    <TemplateRenderer
-                        key={agent?.id + '.' + template.id}
-                        agentId={agent.id}
-                        template={template}
-                        promptCustomizationService={this.promptCustomizationService} />)}
+                {agent.promptTemplates
+                    ?.filter(template => !template.variantOf)
+                    .map(template => (
+                        <div key={agent.id + '.' + template.id}>
+                            <TemplateRenderer
+                                key={agent?.id + '.' + template.id}
+                                agentId={agent.id}
+                                template={template}
+                                promptService={this.promptService}
+                                aiSettingsService={this.aiSettingsService}
+                                promptCustomizationService={this.promptCustomizationService}
+                            />
+                        </div>
+                    ))}
             </div>
+
             <div className='ai-lm-requirements'>
                 <LanguageModelRenderer
                     agent={agent}

packages/ai-core/src/browser/ai-configuration/template-settings-renderer.tsx

@@ -14,26 +14,103 @@
 // SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
 // *****************************************************************************
 import * as React from '@theia/core/shared/react';
-import { PromptCustomizationService } from '../../common/prompt-service';
-import { PromptTemplate } from '../../common';
+import { PromptCustomizationService, PromptService } from '../../common/prompt-service';
+import { AISettingsService, PromptTemplate } from '../../common';
 
-export interface TemplateSettingProps {
+const DEFAULT_VARIANT = 'default';
+
+export interface TemplateRendererProps {
     agentId: string;
     template: PromptTemplate;
     promptCustomizationService: PromptCustomizationService;
+    promptService: PromptService;
+    aiSettingsService: AISettingsService;
 }
 
-export const TemplateRenderer: React.FC<TemplateSettingProps> = ({ agentId, template, promptCustomizationService }) => {
+export const TemplateRenderer: React.FC<TemplateRendererProps> = ({
+    agentId,
+    template,
+    promptCustomizationService,
+    promptService,
+    aiSettingsService,
+}) => {
+    const [variantIds, setVariantIds] = React.useState<string[]>([]);
+    const [selectedVariant, setSelectedVariant] = React.useState<string>(DEFAULT_VARIANT);
+
+    React.useEffect(() => {
+        (async () => {
+            const variants = promptService.getVariantIds(template.id);
+            setVariantIds([DEFAULT_VARIANT, ...variants]);
+
+            const agentSettings = await aiSettingsService.getAgentSettings(agentId);
+            const currentVariant =
+                agentSettings?.selectedVariants?.[template.id] || DEFAULT_VARIANT;
+            setSelectedVariant(currentVariant);
+        })();
+    }, [template.id, promptService, aiSettingsService, agentId]);
+
+    const handleVariantChange = async (event: React.ChangeEvent<HTMLSelectElement>) => {
+        const newVariant = event.target.value;
+        setSelectedVariant(newVariant);
+
+        const agentSettings = await aiSettingsService.getAgentSettings(agentId);
+        const selectedVariants = agentSettings?.selectedVariants || {};
+
+        const updatedVariants = { ...selectedVariants };
+        if (newVariant === DEFAULT_VARIANT) {
+            delete updatedVariants[template.id];
+        } else {
+            updatedVariants[template.id] = newVariant;
+        }
+
+        await aiSettingsService.updateAgentSettings(agentId, {
+            selectedVariants: updatedVariants,
+        });
+    };
+
     const openTemplate = React.useCallback(async () => {
-        promptCustomizationService.editTemplate(template.id, template.template);
-    }, [template, promptCustomizationService]);
+        const templateId = selectedVariant === DEFAULT_VARIANT ? template.id : selectedVariant;
+        const selectedTemplate = promptService.getRawPrompt(templateId);
+        promptCustomizationService.editTemplate(templateId, selectedTemplate?.template || '');
+    }, [selectedVariant, template.id, promptService, promptCustomizationService]);
+
     const resetTemplate = React.useCallback(async () => {
-        promptCustomizationService.resetTemplate(template.id);
-    }, [promptCustomizationService, template]);
-
-    return <>
-        {template.id}
-        <button className='theia-button main' onClick={openTemplate}>Edit</button>
-        <button className='theia-button secondary' onClick={resetTemplate}>Reset</button>
-    </>;
+        const templateId = selectedVariant === DEFAULT_VARIANT ? template.id : selectedVariant;
+        promptCustomizationService.resetTemplate(templateId);
+    }, [selectedVariant, template.id, promptCustomizationService]);
+
+    return (
+        <div className="template-renderer">
+            <div className="settings-section-title template-header">
+                <strong>{template.id}</strong>
+            </div>
+            <div className="template-controls">
+                {variantIds.length > 1 && (
+                    <>
+                        <label htmlFor={`variant-selector-${template.id}`} className="template-select-label">
+                            Variant:
+                        </label>
+                        <select
+                            id={`variant-selector-${template.id}`}
+                            className="theia-select template-variant-selector"
+                            value={selectedVariant}
+                            onChange={handleVariantChange}
+                        >
+                            {variantIds.map(variantId => (
+                                <option key={variantId} value={variantId}>
+                                    {variantId}
+                                </option>
+                            ))}
+                        </select>
+                    </>
+                )}
+                <button className="theia-button main" onClick={openTemplate}>
+                    Edit
+                </button>
+                <button className="theia-button secondary" onClick={resetTemplate}>
+                    Reset
+                </button>
+            </div>
+        </div>
+    );
 };

packages/ai-core/src/browser/style/index.css

@@ -14,14 +14,42 @@
   margin-left: var(--theia-ui-padding);
 }
 
+.theia-settings-container .settings-section-subcategory-title.ai-settings-section-subcategory-title {
+  padding-left: 0;
+}
+
 .ai-templates {
-  display: grid;
-  /** Display content in 3 columns */
-  grid-template-columns: 1fr auto auto;
-  /** add a 3px gap between rows */
-  row-gap: 3px;
+  display: flex;
+  flex-direction: column;
+  gap: 5px;
+}
+
+.template-renderer {
+  display: flex;
+  flex-direction: column;
+  padding: 10px;
+}
+
+.template-header {
+  margin-bottom: 8px;
 }
 
+.template-controls {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+}
+
+.template-select-label {
+  margin-right: 5px;
+}
+
+.template-variant-selector {
+  min-width: 120px;
+}
+
+
+
 #ai-variable-configuration-container-widget,
 #ai-agent-configuration-container-widget {
   margin-top: 5px;

packages/ai-core/src/common/agent-service.ts

@@ -99,7 +99,7 @@ export class AgentServiceImpl implements AgentService {
     registerAgent(agent: Agent): void {
         this._agents.push(agent);
         agent.promptTemplates.forEach(
-            template => this.promptService.storePrompt(template.id, template.template)
+            template => this.promptService.storePromptTemplate(template)
         );
         this.onDidChangeAgentsEmitter.fire();
     }

packages/ai-core/src/common/prompt-service.spec.ts

@@ -244,4 +244,60 @@ describe('PromptService', () => {
         expect(prompt?.text).to.equal('Hi, John! {{!-- Another comment --}}');
     });
 
+    it('should return all variant IDs of a given prompt', () => {
+        promptService.storePromptTemplate({ id: 'main', template: 'Main template' });
+
+        promptService.storePromptTemplate({
+            id: 'variant1',
+            template: 'Variant 1',
+            variantOf: 'main'
+        });
+        promptService.storePromptTemplate({
+            id: 'variant2',
+            template: 'Variant 2',
+            variantOf: 'main'
+        });
+        promptService.storePromptTemplate({
+            id: 'variant3',
+            template: 'Variant 3',
+            variantOf: 'main'
+        });
+
+        const variantIds = promptService.getVariantIds('main');
+        expect(variantIds).to.deep.equal(['variant1', 'variant2', 'variant3']);
+    });
+
+    it('should return an empty array if no variants exist for a given prompt', () => {
+        promptService.storePromptTemplate({ id: 'main', template: 'Main template' });
+
+        const variantIds = promptService.getVariantIds('main');
+        expect(variantIds).to.deep.equal([]);
+    });
+
+    it('should return an empty array if the main prompt ID does not exist', () => {
+        const variantIds = promptService.getVariantIds('nonExistent');
+        expect(variantIds).to.deep.equal([]);
+    });
+
+    it('should not influence prompts without variants when other prompts have variants', () => {
+        promptService.storePromptTemplate({ id: 'mainWithVariants', template: 'Main template with variants' });
+        promptService.storePromptTemplate({ id: 'mainWithoutVariants', template: 'Main template without variants' });
+
+        promptService.storePromptTemplate({
+            id: 'variant1',
+            template: 'Variant 1',
+            variantOf: 'mainWithVariants'
+        });
+        promptService.storePromptTemplate({
+            id: 'variant2',
+            template: 'Variant 2',
+            variantOf: 'mainWithVariants'
+        });
+
+        const variantsForMainWithVariants = promptService.getVariantIds('mainWithVariants');
+        const variantsForMainWithoutVariants = promptService.getVariantIds('mainWithoutVariants');
+
+        expect(variantsForMainWithVariants).to.deep.equal(['variant1', 'variant2']);
+        expect(variantsForMainWithoutVariants).to.deep.equal([]);
+    });
 });

packages/ai-core/src/common/prompt-service.ts

@@ -21,10 +21,16 @@ import { ToolInvocationRegistry } from './tool-invocation-registry';
 import { toolRequestToPromptText } from './language-model-util';
 import { ToolRequest } from './language-model';
 import { matchFunctionsRegEx, matchVariablesRegEx } from './prompt-service-util';
+import { AISettingsService } from './settings-service';
 
 export interface PromptTemplate {
     id: string;
     template: string;
+    /**
+     * (Optional) The ID of the main template for which this template is a variant.
+     * If present, this indicates that the current template represents an alternative version of the specified main template.
+     */
+    variantOf?: string;
 }
 
 export interface PromptMap { [id: string]: PromptTemplate }
@@ -68,6 +74,11 @@ export interface PromptService {
      * @param prompt the prompt template to store
      */
     storePrompt(id: string, prompt: string): void;
+    /**
+     * Adds a {@link PromptTemplate} to the list of prompts.
+     * @param promptTemplate the prompt template to store
+     */
+    storePromptTemplate(promptTemplate: PromptTemplate): void;
     /**
      * Removes a prompt from the list of prompts.
      * @param id the id of the prompt
@@ -77,6 +88,20 @@ export interface PromptService {
      * Return all known prompts as a {@link PromptMap map}.
      */
     getAllPrompts(): PromptMap;
+    /**
+     * Retrieve all variant IDs of a given {@link PromptTemplate}.
+     * @param id the id of the main {@link PromptTemplate}
+     * @returns an array of string IDs representing the variants of the given template
+     */
+    getVariantIds(id: string): string[];
+    /**
+     * Retrieve the currently selected variant ID for a given main prompt ID.
+     * If a variant is selected for the main prompt, it will be returned.
+     * Otherwise, the main prompt ID will be returned.
+     * @param id the id of the main prompt
+     * @returns the variant ID if one is selected, or the main prompt ID otherwise
+     */
+    getVariantId(id: string): Promise<string>;
 }
 
 export interface CustomAgentDescription {
@@ -163,6 +188,9 @@ export interface PromptCustomizationService {
 
 @injectable()
 export class PromptServiceImpl implements PromptService {
+    @inject(AISettingsService) @optional()
+    protected readonly settingsService: AISettingsService | undefined;
+
     @inject(PromptCustomizationService) @optional()
     protected readonly customizationService: PromptCustomizationService | undefined;
 
@@ -203,8 +231,22 @@ export class PromptServiceImpl implements PromptService {
         return commentRegex.test(template) ? template.replace(commentRegex, '').trimStart() : template;
     }
 
+    async getVariantId(id: string): Promise<string> {
+        if (this.settingsService !== undefined) {
+            const agentSettingsMap = await this.settingsService.getSettings();
+
+            for (const agentSettings of Object.values(agentSettingsMap)) {
+                if (agentSettings.selectedVariants && agentSettings.selectedVariants[id]) {
+                    return agentSettings.selectedVariants[id];
+                }
+            }
+        }
+        return id;
+    }
+
     async getPrompt(id: string, args?: { [key: string]: unknown }): Promise<ResolvedPromptTemplate | undefined> {
-        const prompt = this.getUnresolvedPrompt(id);
+        const variantId = await this.getVariantId(id);
+        const prompt = this.getUnresolvedPrompt(variantId);
         if (prompt === undefined) {
             return undefined;
         }
@@ -280,4 +322,12 @@ export class PromptServiceImpl implements PromptService {
     removePrompt(id: string): void {
         delete this._prompts[id];
     }
+    getVariantIds(id: string): string[] {
+        return Object.values(this._prompts)
+            .filter(prompt => prompt.variantOf === id)
+            .map(variant => variant.id);
+    }
+    storePromptTemplate(promptTemplate: PromptTemplate): void {
+        this._prompts[promptTemplate.id] = promptTemplate;
+    }
 }

packages/ai-core/src/common/settings-service.ts

@@ -30,4 +30,9 @@ export type AISettings = Record<string, AgentSettings>;
 export interface AgentSettings {
     languageModelRequirements?: LanguageModelRequirement[];
     enable?: boolean;
+    /**
+     * A mapping of main template IDs to their selected variant IDs.
+     * If a main template is not present in this mapping, it means the main template is used.
+     */
+    selectedVariants?: Record<string, string>;
 }