Generating PR Age Charts

Build an interactive CLI tool that visualizes pull request age distribution for a GitHub repository using Copilot's built-in capabilities.

Runnable example: recipe/pr-visualization.ts

cd recipe && npm install
# Auto-detect from current git repo
npx tsx pr-visualization.ts

# Specify a repo explicitly
npx tsx pr-visualization.ts --repo github/copilot-sdk
# or: npm run pr-visualization

Example scenario

You want to understand how long PRs have been open in a repository. This tool detects the current Git repo or accepts a repo as input, then lets Copilot fetch PR data via the GitHub MCP Server and generate a chart image.

Prerequisites

npm install @github/copilot-sdk
npm install -D typescript tsx @types/node

Usage

# Auto-detect from current git repo
npx tsx pr-visualization.ts

# Specify a repo explicitly
npx tsx pr-visualization.ts --repo github/copilot-sdk

Full example: pr-visualization.ts

#!/usr/bin/env npx tsx

import { execSync } from "node:child_process";
import * as readline from "node:readline";
import { CopilotClient } from "@github/copilot-sdk";

// ============================================================================
// Git & GitHub Detection
// ============================================================================

function isGitRepo(): boolean {
    try {
        execSync("git rev-parse --git-dir", { stdio: "ignore" });
        return true;
    } catch {
        return false;
    }
}

function getGitHubRemote(): string | null {
    try {
        const remoteUrl = execSync("git remote get-url origin", {
            encoding: "utf-8",
        }).trim();

        // Handle SSH: git@github.com:owner/repo.git
        const sshMatch = remoteUrl.match(/git@github\.com:(.+\/.+?)(?:\.git)?$/);
        if (sshMatch) return sshMatch[1];

        // Handle HTTPS: https://github.com/owner/repo.git
        const httpsMatch = remoteUrl.match(/https:\/\/github\.com\/(.+\/.+?)(?:\.git)?$/);
        if (httpsMatch) return httpsMatch[1];

        return null;
    } catch {
        return null;
    }
}

function parseArgs(): { repo?: string } {
    const args = process.argv.slice(2);
    const repoIndex = args.indexOf("--repo");
    if (repoIndex !== -1 && args[repoIndex + 1]) {
        return { repo: args[repoIndex + 1] };
    }
    return {};
}

async function promptForRepo(): Promise<string> {
    const rl = readline.createInterface({
        input: process.stdin,
        output: process.stdout,
    });
    return new Promise((resolve) => {
        rl.question("Enter GitHub repo (owner/repo): ", (answer) => {
            rl.close();
            resolve(answer.trim());
        });
    });
}

// ============================================================================
// Main Application
// ============================================================================

async function main() {
    console.log("🔍 PR Age Chart Generator\n");

    // Determine the repository
    const args = parseArgs();
    let repo: string;

    if (args.repo) {
        repo = args.repo;
        console.log(`📦 Using specified repo: ${repo}`);
    } else if (isGitRepo()) {
        const detected = getGitHubRemote();
        if (detected) {
            repo = detected;
            console.log(`📦 Detected GitHub repo: ${repo}`);
        } else {
            console.log("⚠️  Git repo found but no GitHub remote detected.");
            repo = await promptForRepo();
        }
    } else {
        console.log("📁 Not in a git repository.");
        repo = await promptForRepo();
    }

    if (!repo || !repo.includes("/")) {
        console.error("❌ Invalid repo format. Expected: owner/repo");
        process.exit(1);
    }

    const [owner, repoName] = repo.split("/");

    // Create Copilot client - no custom tools needed!
    const client = new CopilotClient({ logLevel: "error" });

    const session = await client.createSession({
        model: "gpt-5",
        systemMessage: {
            content: `
<context>
You are analyzing pull requests for the GitHub repository: ${owner}/${repoName}
The current working directory is: ${process.cwd()}
</context>

<instructions>
- Use the GitHub MCP Server tools to fetch PR data
- Use your file and code execution tools to generate charts
- Save any generated images to the current working directory
- Be concise in your responses
</instructions>
`,
        },
    });

    // Set up event handling
    const rl = readline.createInterface({
        input: process.stdin,
        output: process.stdout,
    });

    session.on((event) => {
        if (event.type === "assistant.message") {
            console.log(`\n🤖 ${event.data.content}\n`);
        } else if (event.type === "tool.execution_start") {
            console.log(`  ⚙️  ${event.data.toolName}`);
        }
    });

    // Initial prompt - let Copilot figure out the details
    console.log("\n📊 Starting analysis...\n");

    await session.sendAndWait({
        prompt: `
      Fetch the open pull requests for ${owner}/${repoName} from the last week.
      Calculate the age of each PR in days.
      Then generate a bar chart image showing the distribution of PR ages
      (group them into sensible buckets like <1 day, 1-3 days, etc.).
      Save the chart as "pr-age-chart.png" in the current directory.
      Finally, summarize the PR health - average age, oldest PR, and how many might be considered stale.
    `,
    });

    // Interactive loop
    const askQuestion = () => {
        rl.question("You: ", async (input) => {
            const trimmed = input.trim();

            if (trimmed.toLowerCase() === "exit" || trimmed.toLowerCase() === "quit") {
                console.log("👋 Goodbye!");
                rl.close();
                await session.destroy();
                await client.stop();
                process.exit(0);
            }

            if (trimmed) {
                await session.sendAndWait({ prompt: trimmed });
            }

            askQuestion();
        });
    };

    console.log('💡 Ask follow-up questions or type "exit" to quit.\n');
    console.log("Examples:");
    console.log('  - "Expand to the last month"');
    console.log('  - "Show me the 5 oldest PRs"');
    console.log('  - "Generate a pie chart instead"');
    console.log('  - "Group by author instead of age"');
    console.log("");

    askQuestion();
}

main().catch(console.error);

How it works

Repository detection: Checks --repo flag → git remote → prompts user
No custom tools: Relies entirely on Copilot CLI's built-in capabilities:
- GitHub MCP Server - Fetches PR data from GitHub
- File tools - Saves generated chart images
- Code execution - Generates charts using Python/matplotlib or other methods
Interactive session: After initial analysis, user can ask for adjustments

Sample interaction

🔍 PR Age Chart Generator

📦 Using specified repo: CommunityToolkit/Aspire

📊 Starting analysis...

  ⚙️  github-mcp-server-list_pull_requests
  ⚙️  powershell

🤖 I've analyzed 23 open PRs for CommunityToolkit/Aspire:

**PR Age Distribution:**
- < 1 day: 3 PRs
- 1-3 days: 5 PRs
- 3-7 days: 8 PRs
- 1-2 weeks: 4 PRs
- > 2 weeks: 3 PRs

**Summary:**
- Average age: 6.2 days
- Oldest: PR #142 (18 days) - "Add Redis caching support"
- Potentially stale (>7 days): 7 PRs

Chart saved to: pr-age-chart.png

💡 Ask follow-up questions or type "exit" to quit.

You: Expand to the last month and show by author

  ⚙️  github-mcp-server-list_pull_requests
  ⚙️  powershell

🤖 Updated analysis for the last 30 days, grouped by author:

| Author        | Open PRs | Avg Age |
|---------------|----------|---------|
| @contributor1 | 5        | 12 days |
| @contributor2 | 3        | 4 days  |
| @contributor3 | 2        | 8 days  |
| ...           |          |         |

New chart saved to: pr-age-chart.png

You: Generate a pie chart showing the age distribution

  ⚙️  powershell

🤖 Done! Pie chart saved to: pr-age-chart.png

Why this approach?

Aspect	Custom Tools	Built-in Copilot
Code complexity	High	Minimal
Maintenance	You maintain	Copilot maintains
Flexibility	Fixed logic	AI decides best approach
Chart types	What you coded	Any type Copilot can generate
Data grouping	Hardcoded buckets	Intelligent grouping

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