get_github_action

Instructions

Implementation Reference

• src/index.ts:603-660 (handler)

  The core handler function that fetches the specified action.yml file from a GitHub repository using the GitHub API, decodes and parses the YAML content using js-yaml, extracts and formats the inputs and other metadata, and returns a structured representation of the GitHub Action.

  async function getGitHubAction(owner: string, repo: string, path: string = 'action.yml', ref: string = 'main', token?: string) {
    // Use provided token or fall back to config token
    const authToken = token || config.githubToken;
    
    try {
      const headers: Record<string, string> = {
        'Accept': 'application/vnd.github+json',
        'X-GitHub-Api-Version': '2022-11-28'
      };
      
      if (authToken) {
        headers['Authorization'] = `Bearer ${authToken}`;
      }
      
      // First, try to get the action.yml file content
      const contentResponse = await axios.get(
        `https://api.github.com/repos/${owner}/${repo}/contents/${path}?ref=${ref}`,
        { headers }
      );
      
      if (!contentResponse.data.content) {
        throw new Error(`Could not find ${path} file in ${owner}/${repo}`);
      }
      
      // Decode the base64 content
      const content = Buffer.from(contentResponse.data.content, 'base64').toString('utf-8');
      
      // Parse the YAML content
      const yaml = require('js-yaml');
      const actionDefinition = yaml.load(content);
      
      // Extract and format the inputs information
      const inputs = actionDefinition.inputs || {};
      const formattedInputs = Object.entries(inputs).map(([name, config]: [string, any]) => ({
        name,
        description: config.description || '',
        default: config.default,
        required: config.required === true,
        deprecationMessage: config.deprecationMessage,
      }));
      
      return {
        name: actionDefinition.name || '',
        description: actionDefinition.description || '',
        author: actionDefinition.author || '',
        inputs: formattedInputs,
        runs: actionDefinition.runs,
        branding: actionDefinition.branding,
        // Include original content for reference
        originalYaml: content
      };
    } catch (error) {
      if (axios.isAxiosError(error)) {
        throw new Error(`GitHub API error: ${error.response?.status} ${error.response?.statusText} - ${error.response?.data?.message || error.message}`);
      }
      throw error;
    }
  }

• src/index.ts:131-159 (registration)

  Registers the 'get_github_action' tool in the MCP server's listTools response, including its name, description, and input schema definition.

    name: "get_github_action",
    description: "Get detailed information about a specific GitHub Action, including inputs and their requirements",
    inputSchema: {
      type: "object",
      properties: {
        owner: {
          type: "string",
          description: "Owner of the action (username or organization)"
        },
        repo: {
          type: "string",
          description: "Repository name of the action"
        },
        path: {
          type: "string",
          description: "Path to the action.yml or action.yaml file (usually just 'action.yml')"
        },
        ref: {
          type: "string",
          description: "Git reference (branch, tag, or commit SHA, default: main)"
        },
        token: {
          type: "string",
          description: "GitHub personal access token (optional)"
        }
      },
      required: ["owner", "repo"]
    }
  },

• src/index.ts:133-158 (schema)

  Defines the input schema for the 'get_github_action' tool, specifying properties like owner, repo, path, ref, token, with owner and repo required.

  inputSchema: {
    type: "object",
    properties: {
      owner: {
        type: "string",
        description: "Owner of the action (username or organization)"
      },
      repo: {
        type: "string",
        description: "Repository name of the action"
      },
      path: {
        type: "string",
        description: "Path to the action.yml or action.yaml file (usually just 'action.yml')"
      },
      ref: {
        type: "string",
        description: "Git reference (branch, tag, or commit SHA, default: main)"
      },
      token: {
        type: "string",
        description: "GitHub personal access token (optional)"
      }
    },
    required: ["owner", "repo"]
  }

• src/index.ts:754-780 (handler)

  The MCP CallToolRequestHandler case that handles incoming calls to 'get_github_action', extracts arguments, validates inputs, calls the getGitHubAction function, and returns the result as MCP content.

  case "get_github_action": {
    const owner = String(request.params.arguments?.owner);
    const repo = String(request.params.arguments?.repo);
    const path = request.params.arguments?.path ? String(request.params.arguments?.path) : 'action.yml';
    const ref = request.params.arguments?.ref ? String(request.params.arguments?.ref) : 'main';
    const token = request.params.arguments?.token ? String(request.params.arguments?.token) : undefined;
    
    if (!owner || !repo) {
      throw new Error("Owner and repo are required");
    }
  
    try {
      const actionDetails = await getGitHubAction(owner, repo, path, ref, token);
      
      return {
        content: [{
          type: "text",
          text: JSON.stringify(actionDetails, null, 2)
        }]
      };
    } catch (error) {
      if (error instanceof Error) {
        throw new Error(`Failed to get GitHub Action details: ${error.message}`);
      }
      throw error;
    }
  }