--- season: 2 season_name: "Season 2 โ€” March 2026 (Spring Cherry Blossom Edition)" day: 4 title: "MCP Servers: Add external tools to your agents in just a few lines" summary: "Wire up multiple MCP servers simultaneously to trace bugs from Linear to GitHub PRs." tags: ["Code Analysis", "Tool Call", "MCP", "ADK"] canonical_url: "https://adventofagents.com/2026/03/04" markdown_url: "https://adventofagents.com/2026/03/04.md" video_url: "https://www.youtube.com/embed/to4k4aPlYDw" --- # ๐Ÿž Day 4: MCP Servers: Add external tools to your agents in just a few lines > **Season 2 โ€” March 2026 (Spring Cherry Blossom Edition)** ยท [Interactive Web View](https://adventofagents.com/2026/03/04?utm_source=adventofagents&utm_medium=markdown&utm_campaign=adventofagents_s2_2026&utm_content=day04) ยท [Raw Markdown](https://adventofagents.com/2026/03/04.md?utm_source=adventofagents&utm_medium=markdown&utm_campaign=adventofagents_s2_2026&utm_content=day04) **Summary:** Wire up multiple MCP servers simultaneously to trace bugs from Linear to GitHub PRs. **Day 4 of Google's Advent of Agents โ€” Season 2** Connecting a single external tool to an agent is useful, but routing context across multiple specialized tools unlocks complex workflows. ๐ŸŒ The **Model Context Protocol (MCP)** standardizes how agents access these diverse data sources. By configuring our triage agent with both the **GitHub** and **Linear** MCP servers simultaneously, it can cross-reference system records natively without manual intervention! ๐Ÿค–โœจ **๐Ÿ› The Triaging Workflow** When diagnosing a reported bug, developers typically piece together context across issue trackers and version control. We can automate this painful triaging process: 1. **Bug Extraction:** The agent first queries the `[Linear MCP Server](https://github.com/modelcontextprotocol/servers/tree/main/src/linear?utm_source=adventofagents&utm_medium=markdown&utm_campaign=adventofagents_s2_2026&utm_content=day04)` to extract the details of a specific bug report. ๐Ÿ“‹ 2. **Context Routing:** Using those identifiers or branch names, the agent seamlessly pivots to query the `[GitHub MCP Server](https://github.com/modelcontextprotocol/servers/tree/main/src/github?utm_source=adventofagents&utm_medium=markdown&utm_campaign=adventofagents_s2_2026&utm_content=day04)` to locate the corresponding pull request. ๐Ÿ”€ 3. **Analysis & Summary:** Finally, it analyzes the code diffs and summarizes the exact changes introduced, bridging the gap between the product issue and the committed code. ๐Ÿ”๐Ÿ’ป. Say goodbye to context-switching between tabs! ๐ŸŽ‰ ## Code & Commands ```python from google.adk.agents import Agent from google.adk.models import Gemini from google.adk.apps import App from google.adk.tools.mcp_tool import McpToolset from google.adk.tools.mcp_tool.mcp_session_manager import StreamableHTTPServerParams import os GITHUB_TOKEN = os.environ.get("GITHUB_TOKEN") LINEAR_API_KEY = os.environ.get("LINEAR_API_KEY") root_agent = Agent( model=Gemini(model="gemini-3-flash-preview"), name="root_agent", instruction=open(os.path.join(os.path.dirname(__file__), "prompt.md")).read(), tools=[ McpToolset( tool_name_prefix="github_", connection_params=StreamableHTTPServerParams( url="https://api.githubcopilot.com/mcp/", headers={ "Authorization": f"Bearer {GITHUB_TOKEN}", "X-MCP-Toolsets": "pull_requests", "X-MCP-Readonly": "true" }, ), ), McpToolset( tool_name_prefix="linear_", tool_filter=["get_issue", "list_issues", "search_issues"], connection_params=StreamableHTTPServerParams( url="https://mcp.linear.app/mcp", headers={ "Authorization": f"Bearer {LINEAR_API_KEY}", }, ), ) ], ) app = App( name="app", root_agent=root_agent, ) ``` ```markdown You are an intelligent agent that can fetch the source diff of a Pull Request based on the Linear issue ID. Your exact workflow is: 1. Use `linear_get_issue` to fetch the specific bug report in Linear. 2. Extract keywords, branch names, or the exact title from the Linear issue. 3. Use `github_list_pull_requests` or `github_search_pull_requests` in the provided GitHub repository using those extracted keywords to find the associated Pull Request. Important: Always restrict your search to the user's provided repository (e.g. `repo:rovindra/web-master`) rather than searching globally. Do not search by the literal Linear issue ID unless you know it's in the PR title. 4. Use `github_pull_request_read` to fetch the source diff of that exact PR. 5. Summarize the diff based on the PR contents. When returning the final response, you MUST format the details as a markdown table followed by the diff summary: | Field | Details | |---|---| | **Title** | [PR Title] | | **Author** | [PR Author] | | **Branch** | [PR Branch] | | **Date** | [PR Date] | | **Files Changed** | [PR No. of Files Changed] | | **State** | [Open/Merged/Closed] | | **Issue** | [Linear Issue ID & Title] | | **Description** | [Brief PR Description] | | **Summary** | [Your brief summary of the changes] | ### Diff Analysis [Detailed explanation of the code changes...] ### Diff [Actual diff of the changes...] Never ask the user for a PR number if they already provided the target GitHub repository and Linear issue ID. ``` ## Resources & Links - **[Developer Blog](https://developers.googleblog.com/en/supercharge-your-ai-agents-adk-integrations-ecosystem/?utm_source=adventofagents&utm_medium=markdown&utm_campaign=adventofagents_s2_2026&utm_content=day04)** โ€” Supercharge your AI Agents: Details on ADK Integrations Ecosystem - **[Model Context Protocol Documentation](https://modelcontextprotocol.io/)** โ€” Standardizing how agents access diverse data sources - **[GitHub MCP Server](https://google.github.io/adk-docs/integrations/github?utm_source=adventofagents&utm_medium=markdown&utm_campaign=adventofagents_s2_2026&utm_content=day04)** โ€” GitHub MCP Server implementation - **[Linear MCP Server](https://google.github.io/adk-docs/integrations/linear?utm_source=adventofagents&utm_medium=markdown&utm_campaign=adventofagents_s2_2026&utm_content=day04)** โ€” Linear MCP Server implementation