claude-code-action/src/entrypoints/prepare.ts

#!/usr/bin/env bun

/**
 * Prepare the Claude action by checking trigger conditions, verifying human actor,
 * and creating the initial tracking comment
 */

import * as core from "@actions/core";
import { setupGitHubToken } from "../github/token";
import { checkWritePermissions } from "../github/validation/permissions";
import { createOctokit } from "../github/api/client";
import { parseGitHubContext, isEntityContext } from "../github/context";
import { getMode, isValidMode, DEFAULT_MODE } from "../modes/registry";
import type { ModeName } from "../modes/types";
import { prepare } from "../prepare";

async function run() {
  try {
    // Step 1: Get mode first to determine authentication method
    const modeInput = process.env.MODE || DEFAULT_MODE;

    // Validate mode input
    if (!isValidMode(modeInput)) {
      throw new Error(`Invalid mode: ${modeInput}`);
    }
    const validatedMode: ModeName = modeInput;

    // Step 2: Setup GitHub token based on mode
    let githubToken: string;
    if (validatedMode === "experimental-review") {
      // For experimental-review mode, use the default GitHub Action token
      githubToken = process.env.DEFAULT_WORKFLOW_TOKEN || "";
      if (!githubToken) {
        throw new Error(
          "DEFAULT_WORKFLOW_TOKEN not found for experimental-review mode",
        );
      }
      console.log("Using default GitHub Action token for review mode");
      core.setOutput("GITHUB_TOKEN", githubToken);
    } else {
      // For other modes, use the existing token exchange
      githubToken = await setupGitHubToken();
    }
    const octokit = createOctokit(githubToken);

    // Step 2: Parse GitHub context (once for all operations)
    const context = parseGitHubContext();

    // Step 3: Check write permissions (only for entity contexts)
    if (isEntityContext(context)) {
      const hasWritePermissions = await checkWritePermissions(
        octokit.rest,
        context,
      );
      if (!hasWritePermissions) {
        throw new Error(
          "Actor does not have write permissions to the repository",
        );
      }
    }

    // Step 4: Get mode and check trigger conditions
    const mode = getMode(validatedMode, context);
    const containsTrigger = mode.shouldTrigger(context);

    // Set output for action.yml to check
    core.setOutput("contains_trigger", containsTrigger.toString());

    if (!containsTrigger) {
      console.log("No trigger found, skipping remaining steps");
      return;
    }

    // Step 5: Use the new modular prepare function
    const result = await prepare({
      context,
      octokit,
      mode,
      githubToken,
    });

    // Set the MCP config output
    core.setOutput("mcp_config", result.mcpConfig);

    // Step 6: Get system prompt from mode if available
    if (mode.getSystemPrompt) {
      const modeContext = mode.prepareContext(context, {
        commentId: result.commentId,
        baseBranch: result.branchInfo.baseBranch,
        claudeBranch: result.branchInfo.claudeBranch,
      });
      const systemPrompt = mode.getSystemPrompt(modeContext);
      if (systemPrompt) {
        core.exportVariable("APPEND_SYSTEM_PROMPT", systemPrompt);
      }
    }
  } catch (error) {
    const errorMessage = error instanceof Error ? error.message : String(error);
    core.setFailed(`Prepare step failed with error: ${errorMessage}`);
    // Also output the clean error message for the action to capture
    core.setOutput("prepare_error", errorMessage);
    process.exit(1);
  }
}

if (import.meta.main) {
  run();
}