feat: expose file download feature outside of tag mode

docs/usage.md

@@ -211,3 +211,20 @@ Upload a screenshot of a bug and ask Claude to fix it:
 ```
 
 Claude can see and analyze images, making it easy to fix visual bugs or UI issues.
+
+### Analyze Images with GitHub Assets
+
+For automation workflows that need to analyze images from GitHub issues or PRs, GitHub assets (images, attachments) are automatically downloaded when running in entity contexts (issue comments, pull requests, etc.):
+
+```yaml
+- uses: anthropics/claude-code-action@v1
+  with:
+    anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
+    prompt: |
+      Analyze any images attached to this issue/PR.
+
+      GitHub assets are automatically downloaded and available via CLAUDE_ASSET_FILES environment variable.
+      Use the Read tool to access and analyze each image file.
+```
+
+Images from GitHub issues and PRs are automatically downloaded and made available to Claude through the `CLAUDE_ASSET_FILES` environment variable when running in entity contexts.

examples/agent-with-assets.yml

@@ -0,0 +1,24 @@
+name: Agent Mode Asset Analysis
+on:
+  issue_comment:
+    types: [created]
+
+jobs:
+  analyze:
+    if: contains(github.event.comment.body, '@claude')
+    runs-on: ubuntu-latest
+    steps:
+      - uses: anthropics/claude-code-action@v1
+        with:
+          anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
+          prompt: |
+            Analyze the images from this GitHub issue/PR.
+
+            GitHub assets (images, attachments) are automatically downloaded and available 
+            in the CLAUDE_ASSET_FILES environment variable.
+            You can use bash commands to process this environment variable and access the files.
+
+            For example, list the files with:
+            `echo $CLAUDE_ASSET_FILES | tr ',' '\n'`
+
+            Then use the Read tool to analyze each file.

src/modes/agent/index.ts

@@ -5,6 +5,8 @@ import type { PreparedContext } from "../../create-prompt/types";
 import { prepareMcpConfig } from "../../mcp/install-mcp-server";
 import { parseAllowedTools } from "./parse-tools";
 import { configureGitAuth } from "../../github/operations/git-config";
+import { fetchGitHubData } from "../../github/data/fetcher";
+import { isEntityContext } from "../../github/context";
 
 /**
  * Agent mode implementation.
@@ -122,6 +124,36 @@ export const agentMode: Mode = {
     // Append user's claude_args (which may have more --mcp-config flags)
     claudeArgs = `${claudeArgs} ${userClaudeArgs}`.trim();
 
+    // Download GitHub assets automatically for entity contexts
+    if (isEntityContext(context)) {
+      console.log("Downloading GitHub assets for agent mode...");
+
+      try {
+        // Fetch GitHub data (reuse existing logic)
+        const githubData = await fetchGitHubData({
+          octokits: octokit,
+          repository: `${context.repository.owner}/${context.repository.repo}`,
+          prNumber: context.entityNumber.toString(),
+          isPR: context.isPR,
+          triggerUsername: context.actor,
+        });
+
+        // Set simple environment variable with comma-separated paths
+        const downloadedPaths = Array.from(githubData.imageUrlMap.values());
+        if (downloadedPaths.length > 0) {
+          const concatDownloadedPaths = downloadedPaths.join(",");
+          process.env.CLAUDE_ASSET_FILES = concatDownloadedPaths;
+          core.exportVariable("CLAUDE_ASSET_FILES", concatDownloadedPaths);
+          console.log(
+            `Exposed ${downloadedPaths.length} assets: ${concatDownloadedPaths}`,
+          );
+        }
+      } catch (error) {
+        console.error("Failed to download GitHub assets:", error);
+        // Continue execution - don't fail the entire action
+      }
+    }
+
     core.setOutput("claude_args", claudeArgs);
 
     return {

test/modes/agent.test.ts

@@ -3,6 +3,7 @@ import { agentMode } from "../../src/modes/agent";
 import type { GitHubContext } from "../../src/github/context";
 import { createMockContext, createMockAutomationContext } from "../mockContext";
 import * as core from "@actions/core";
+import * as fetcher from "../../src/github/data/fetcher";
 
 describe("Agent Mode", () => {
   let mockContext: GitHubContext;
@@ -166,4 +167,121 @@ describe("Agent Mode", () => {
     expect(callArgs[0]).toBe("claude_args");
     expect(callArgs[1]).toContain("--mcp-config");
   });
+
+  test("automatically downloads GitHub assets for entity context", async () => {
+    // Mock the fetchGitHubData function
+    const mockImageMap = new Map([
+      [
+        "https://github.com/user-attachments/assets/image1",
+        "/tmp/github-images/image-123.png",
+      ],
+      [
+        "https://github.com/user-attachments/assets/image2",
+        "/tmp/github-images/image-456.jpg",
+      ],
+    ]);
+    const fetchSpy = spyOn(fetcher, "fetchGitHubData").mockResolvedValue({
+      contextData: {} as any,
+      comments: [],
+      changedFiles: [],
+      changedFilesWithSHA: [],
+      reviewData: null,
+      imageUrlMap: mockImageMap,
+      triggerDisplayName: null,
+    });
+
+    // Create an entity context (issue comment)
+    const entityContext = createMockContext({
+      eventName: "issue_comment",
+      inputs: { prompt: "Analyze images" },
+    });
+
+    const mockOctokit = {} as any;
+
+    await agentMode.prepare({
+      context: entityContext,
+      octokit: mockOctokit,
+      githubToken: "test-token",
+    });
+
+    // Verify fetchGitHubData was called
+    expect(fetchSpy).toHaveBeenCalledTimes(1);
+    expect(fetchSpy).toHaveBeenCalledWith({
+      octokits: mockOctokit,
+      repository: `${entityContext.repository.owner}/${entityContext.repository.repo}`,
+      prNumber: entityContext.entityNumber.toString(),
+      isPR: entityContext.isPR,
+      triggerUsername: entityContext.actor,
+    });
+
+    // Verify CLAUDE_ASSET_FILES environment variable was set
+    expect(process.env.CLAUDE_ASSET_FILES).toBe(
+      "/tmp/github-images/image-123.png,/tmp/github-images/image-456.jpg",
+    );
+
+    // Verify core.exportVariable was called with correct arguments
+    expect(exportVariableSpy).toHaveBeenCalledWith(
+      "CLAUDE_ASSET_FILES",
+      "/tmp/github-images/image-123.png,/tmp/github-images/image-456.jpg",
+    );
+
+    // Clean up
+    delete process.env.CLAUDE_ASSET_FILES;
+    fetchSpy.mockRestore();
+  });
+
+  test("skips asset download for non-entity contexts", async () => {
+    const fetchSpy = spyOn(fetcher, "fetchGitHubData");
+
+    // Create an automation context (workflow_dispatch)
+    const automationContext = createMockAutomationContext({
+      eventName: "workflow_dispatch",
+      inputs: { prompt: "Analyze something" },
+    });
+
+    const mockOctokit = {} as any;
+
+    await agentMode.prepare({
+      context: automationContext,
+      octokit: mockOctokit,
+      githubToken: "test-token",
+    });
+
+    // Verify fetchGitHubData was NOT called for automation contexts
+    expect(fetchSpy).toHaveBeenCalledTimes(0);
+    expect(process.env.CLAUDE_ASSET_FILES).toBeUndefined();
+
+    fetchSpy.mockRestore();
+  });
+
+  test("handles asset download errors gracefully", async () => {
+    const consoleSpy = spyOn(console, "error").mockImplementation(() => {});
+    const fetchSpy = spyOn(fetcher, "fetchGitHubData").mockRejectedValue(
+      new Error("Network error"),
+    );
+
+    const entityContext = createMockContext({
+      eventName: "issue_comment",
+      inputs: { prompt: "Analyze images" },
+    });
+
+    const mockOctokit = {} as any;
+
+    // This should not throw despite the error
+    await agentMode.prepare({
+      context: entityContext,
+      octokit: mockOctokit,
+      githubToken: "test-token",
+    });
+
+    // Verify error was logged but execution continued
+    expect(consoleSpy).toHaveBeenCalledWith(
+      "Failed to download GitHub assets:",
+      expect.any(Error),
+    );
+    expect(process.env.CLAUDE_ASSET_FILES).toBeUndefined();
+
+    fetchSpy.mockRestore();
+    consoleSpy.mockRestore();
+  });
 });