Add optional context to PR description generation (#270)

* types: add optional context parameter to generatePullRequestDescription signature

* api: update gitApi to pass optional context to PR description generation

* http: include trimmed context in PR description API request body

* ui: add additional context input for PR generation with desktop disclosure and mobile sheet

* desktop: pass optional context to Tauri generate_pr_description command

* tauri: add optional context parameter and inject into PR description prompt

* server: read optional context from request and inject into PR description prompt

* vscode: update type signature for context parameter (compatibility only)

* fix(vscode): drop context from pr-description payload

Remove context field from PR description payload
Send only base and head to the bridge API for PR descriptions
Clarify payload compatibility across web/desktop environments

packages/desktop/src-tauri/src/commands/git.rs

@@ -2343,6 +2343,7 @@ pub async fn generate_pr_description(
     directory: String,
     base: String,
     head: String,
+    context: Option<String>,
     state: State<'_, DesktopRuntime>,
 ) -> Result<serde_json::Value, String> {
     let root = validate_git_path(&directory, state.settings())
@@ -2398,8 +2399,8 @@ pub async fn generate_pr_description(
     }
 
     // 2. Construct PR-specific prompt
-    let prompt = format!(
+    let mut prompt = format!(
-        r#"You are drafting a GitHub Pull Request title + description. Respond in JSON of the shape {{\"title\": string, \"body\": string}} (ONLY JSON in response, no markdown fences) with these rules:
+        r#"You are drafting a GitHub Pull Request title + description. Respond in JSON of the shape {{"title": string, "body": string}} (ONLY JSON in response, no markdown fences) with these rules:
 - title: concise, sentence case, <= 80 chars, no trailing punctuation, no commit-style prefixes (no \"feat:\", \"fix:\")
 - body: GitHub-flavored markdown with these sections in this order: Summary, Testing, Notes
 - Summary: 3-6 bullet points describing user-visible changes; avoid internal helper function names
@@ -2407,15 +2408,21 @@ pub async fn generate_pr_description(
 - Notes: bullet list; include breaking/rollout notes only when relevant
 Context:
 - base branch: {base}
-- head branch: {head}
+- head branch: {head}"#,
-
-Diff summary:
-{diffs}"#,
         base = base.trim(),
-        head = head.trim(),
+        head = head.trim()
-        diffs = diff_summaries
     );
 
+    // Include additional context if provided
+    if let Some(ctx) = context {
+        let trimmed = ctx.trim();
+        if !trimmed.is_empty() {
+            prompt.push_str(&format!("\n\nAdditional context provided by user:\n{}", trimmed));
+        }
+    }
+
+    prompt.push_str(&format!("\n\nDiff summary:\n{}", diff_summaries));
+
     let model = "gpt-5-nano";
 
     // 3. Call API

packages/desktop/src/api/git.ts

@@ -111,13 +111,17 @@ export const createDesktopGitAPI = (): GitAPI => ({
 
   async generatePullRequestDescription(
     directory: string,
-    payload: { base: string; head: string }
+    payload: { base: string; head: string; context?: string }
   ): Promise<GeneratedPullRequestDescription> {
-    return safeGitInvoke<GeneratedPullRequestDescription>('generate_pr_description', {
+    const params: { directory: string; base: string; head: string; context?: string } = {
       directory,
       base: payload.base,
       head: payload.head,
-    });
+    };
+    if (payload.context?.trim()) {
+      params.context = payload.context.trim();
+    }
+    return safeGitInvoke<GeneratedPullRequestDescription>('generate_pr_description', params);
   },
 
   async listGitWorktrees(directory: string): Promise<GitWorktreeInfo[]> {

packages/ui/src/components/views/git/PullRequestSection.tsx

@@ -25,6 +25,8 @@ import {
 } from '@/components/ui/collapsible';
 import { generatePullRequestDescription } from '@/lib/gitApi';
 import { useRuntimeAPIs } from '@/hooks/useRuntimeAPIs';
+import { useDeviceInfo } from '@/lib/device';
+import { MobileOverlayPanel } from '@/components/ui/MobileOverlayPanel';
 import { useUIStore } from '@/stores/useUIStore';
 import { useMessageStore } from '@/stores/messageStore';
 import { useSessionStore } from '@/stores/useSessionStore';
@@ -66,6 +68,7 @@ type PullRequestDraftSnapshot = {
   body: string;
   draft: boolean;
   isOpen: boolean;
+  additionalContext: string;
 };
 
 const pullRequestDraftSnapshots = new Map<string, PullRequestDraftSnapshot>();
@@ -102,6 +105,7 @@ export const PullRequestSection: React.FC<{
   const setSidebarSection = useUIStore((state) => state.setSidebarSection);
   const setActiveMainTab = useUIStore((state) => state.setActiveMainTab);
   const currentSessionId = useSessionStore((state) => state.currentSessionId);
+  const { isMobile } = useDeviceInfo();
 
   const openGitHubSettings = React.useCallback(() => {
     setSidebarSection('settings');
@@ -122,6 +126,7 @@ export const PullRequestSection: React.FC<{
   const [title, setTitle] = React.useState(() => initialSnapshot?.title ?? branchToTitle(branch));
   const [body, setBody] = React.useState(() => initialSnapshot?.body ?? '');
   const [draft, setDraft] = React.useState(() => initialSnapshot?.draft ?? false);
+  const [additionalContext, setAdditionalContext] = React.useState(() => initialSnapshot?.additionalContext ?? '');
   const [mergeMethod, setMergeMethod] = React.useState<MergeMethod>('squash');
 
   const [isGenerating, setIsGenerating] = React.useState(false);
@@ -129,6 +134,9 @@ export const PullRequestSection: React.FC<{
   const [isMerging, setIsMerging] = React.useState(false);
   const [isMarkingReady, setIsMarkingReady] = React.useState(false);
 
+  const [isContextOpen, setIsContextOpen] = React.useState(false);
+  const [isContextSheetOpen, setIsContextSheetOpen] = React.useState(false);
+
   const [checksDialogOpen, setChecksDialogOpen] = React.useState(false);
   const [checkDetails, setCheckDetails] = React.useState<GitHubPullRequestContextResult | null>(null);
   const [isLoadingCheckDetails, setIsLoadingCheckDetails] = React.useState(false);
@@ -407,8 +415,9 @@ export const PullRequestSection: React.FC<{
       body,
       draft,
       isOpen,
+      additionalContext,
     });
-  }, [snapshotKey, title, body, draft, isOpen, directory, branch]);
+  }, [snapshotKey, title, body, draft, isOpen, additionalContext, directory, branch]);
 
   const generateDescription = React.useCallback(async () => {
     if (isGenerating) return;
@@ -418,6 +427,7 @@ export const PullRequestSection: React.FC<{
       const generated = await generatePullRequestDescription(directory, {
         base: baseBranch,
         head: branch,
+        context: additionalContext,
       });
 
       if (generated.title?.trim()) {
@@ -433,7 +443,7 @@ export const PullRequestSection: React.FC<{
     } finally {
       setIsGenerating(false);
     }
-  }, [baseBranch, branch, directory, isGenerating]);
+  }, [baseBranch, branch, directory, isGenerating, additionalContext]);
 
   const createPr = React.useCallback(async () => {
     if (!github?.prCreate) {
@@ -731,6 +741,84 @@ export const PullRequestSection: React.FC<{
                   <span className="typography-ui-label text-foreground select-none">Draft</span>
                 </div>
 
+                {/* Additional Context Section */}
+                {isMobile ? (
+                  <div className="space-y-2">
+                    <div className="flex items-center justify-between gap-2">
+                      <span className="typography-micro text-muted-foreground">
+                        Additional context (optional)
+                      </span>
+                      <Button
+                        variant="outline"
+                        size="sm"
+                        onClick={() => setIsContextSheetOpen(true)}
+                      >
+                        {additionalContext.trim() ? 'Edit' : 'Add'}
+                      </Button>
+                    </div>
+                    {additionalContext.trim() && (
+                      <div className="flex items-center gap-2">
+                        <span className="inline-flex items-center rounded-full bg-[var(--interactive-selection)] px-2 py-0.5 text-xs text-[var(--interactive-selection-foreground)]">
+                          Context added
+                        </span>
+                      </div>
+                    )}
+                  </div>
+                ) : (
+                  <Collapsible open={isContextOpen} onOpenChange={setIsContextOpen}>
+                    <CollapsibleTrigger className="flex w-full items-center justify-between rounded-lg border border-[var(--interactive-border)] bg-[var(--surface-elevated)] px-3 py-2 hover:bg-[var(--interactive-hover)]">
+                      <span className="typography-micro text-muted-foreground">
+                        Additional context (optional)
+                      </span>
+                      <span className="typography-micro text-[var(--primary-base)]">
+                        {isContextOpen ? 'Hide' : additionalContext.trim() ? 'Edit' : 'Add'}
+                      </span>
+                    </CollapsibleTrigger>
+                    <CollapsibleContent>
+                      <div className="mt-2 space-y-2 rounded-lg border border-[var(--interactive-border)] bg-[var(--surface-elevated)] p-3">
+                        <Textarea
+                          value={additionalContext}
+                          onChange={(e) => setAdditionalContext(e.target.value)}
+                          className="min-h-[100px] bg-transparent"
+                          placeholder="Explain why this change is needed...&#10;Mention how to test (commands / steps)...&#10;Call out risks / rollout plan..."
+                        />
+                        <p className="typography-micro text-muted-foreground">
+                          This text is only used to guide PR generation.
+                        </p>
+                      </div>
+                    </CollapsibleContent>
+                  </Collapsible>
+                )}
+
+                {/* Mobile Sheet for Context */}
+                <MobileOverlayPanel
+                  open={isContextSheetOpen}
+                  onClose={() => setIsContextSheetOpen(false)}
+                  title="Additional context"
+                  footer={
+                    <Button
+                      size="sm"
+                      onClick={() => setIsContextSheetOpen(false)}
+                      className="w-full"
+                    >
+                      Done
+                    </Button>
+                  }
+                >
+                  <div className="space-y-3">
+                    <Textarea
+                      value={additionalContext}
+                      onChange={(e) => setAdditionalContext(e.target.value)}
+                      className="min-h-[200px] bg-transparent"
+                      placeholder="Explain why this change is needed...&#10;Mention how to test (commands / steps)...&#10;Call out risks / rollout plan..."
+                      autoFocus
+                    />
+                    <p className="typography-micro text-muted-foreground">
+                      This text is only used to guide PR generation.
+                    </p>
+                  </div>
+                </MobileOverlayPanel>
+
                 <div className="flex items-center gap-2">
                   <Button
                     variant="outline"

packages/ui/src/lib/api/types.ts

@@ -287,7 +287,7 @@ export interface GitAPI {
   generateCommitMessage(directory: string, files: string[]): Promise<{ message: GeneratedCommitMessage }>;
   generatePullRequestDescription(
     directory: string,
-    payload: { base: string; head: string }
+    payload: { base: string; head: string; context?: string }
   ): Promise<GeneratedPullRequestDescription>;
   listGitWorktrees(directory: string): Promise<GitWorktreeInfo[]>;
   addGitWorktree(directory: string, payload: GitAddWorktreePayload): Promise<{ success: boolean; path: string; branch: string }>;

packages/ui/src/lib/gitApi.ts

@@ -106,7 +106,7 @@ export async function generateCommitMessage(
 
 export async function generatePullRequestDescription(
   directory: string,
-  payload: { base: string; head: string }
+  payload: { base: string; head: string; context?: string }
 ): Promise<import('./api/types').GeneratedPullRequestDescription> {
   const runtime = getRuntimeGit();
   if (runtime?.generatePullRequestDescription) {

packages/ui/src/lib/gitApiHttp.ts

@@ -250,17 +250,22 @@ export async function generateCommitMessage(
 
 export async function generatePullRequestDescription(
   directory: string,
-  payload: { base: string; head: string }
+  payload: { base: string; head: string; context?: string }
 ): Promise<{ title: string; body: string }> {
-  const { base, head } = payload;
+  const { base, head, context } = payload;
   if (!base || !head) {
     throw new Error('base and head are required');
   }
 
+  const requestBody: { base: string; head: string; context?: string } = { base, head };
+  if (context?.trim()) {
+    requestBody.context = context.trim();
+  }
+
   const response = await fetch(buildUrl(`${API_BASE}/pr-description`, directory), {
     method: 'POST',
     headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify({ base, head }),
+    body: JSON.stringify(requestBody),
   });
 
   if (!response.ok) {

packages/web/server/index.js

@@ -5983,6 +5983,7 @@ async function main(options = {}) {
 
       const base = typeof req.body?.base === 'string' ? req.body.base.trim() : '';
       const head = typeof req.body?.head === 'string' ? req.body.head.trim() : '';
+      const context = typeof req.body?.context === 'string' ? req.body.context.trim() : '';
       if (!base || !head) {
         return res.status(400).json({ error: 'base and head are required' });
       }
@@ -6002,7 +6003,22 @@ async function main(options = {}) {
 
       const diffSummaries = diffs.map(({ path, diff }) => `FILE: ${path}\n${diff}`).join('\n\n');
 
-      const prompt = `You are drafting a GitHub Pull Request title + description. Respond in JSON of the shape {"title": string, "body": string} (ONLY JSON in response, no markdown fences) with these rules:\n- title: concise, sentence case, <= 80 chars, no trailing punctuation, no commit-style prefixes (no "feat:", "fix:")\n- body: GitHub-flavored markdown with these sections in this order: Summary, Testing, Notes\n- Summary: 3-6 bullet points describing user-visible changes; avoid internal helper function names\n- Testing: bullet list ("- Not tested" allowed)\n- Notes: bullet list; include breaking/rollout notes only when relevant\n\nContext:\n- base branch: ${base}\n- head branch: ${head}\n\nDiff summary:\n${diffSummaries}`;
+      let prompt = `You are drafting a GitHub Pull Request title + description. Respond in JSON of the shape {"title": string, "body": string} (ONLY JSON in response, no markdown fences) with these rules:
+- title: concise, sentence case, <= 80 chars, no trailing punctuation, no commit-style prefixes (no "feat:", "fix:")
+- body: GitHub-flavored markdown with these sections in this order: Summary, Testing, Notes
+- Summary: 3-6 bullet points describing user-visible changes; avoid internal helper function names
+- Testing: bullet list ("- Not tested" allowed)
+- Notes: bullet list; include breaking/rollout notes only when relevant
+
+Context:
+- base branch: ${base}
+- head branch: ${head}`;
+
+      if (context) {
+        prompt += `\n\nAdditional context provided by user:\n${context}`;
+      }
+
+      prompt += `\n\nDiff summary:\n${diffSummaries}`;
 
       const model = 'gpt-5-nano';