add code coverage command

crates/g3-core/src/lib.rs

@@ -2158,6 +2158,15 @@ impl<W: UiWriter> Agent<W> {
                     "required": ["content"]
                 }),
             },
+            Tool {
+                name: "code_coverage".to_string(),
+                description: "Generate a code coverage report for the entire workspace using cargo llvm-cov. This runs all tests with coverage instrumentation and returns a summary of coverage statistics. Requires llvm-tools-preview and cargo-llvm-cov to be installed (they will be auto-installed if missing).".to_string(),
+                input_schema: json!({
+                    "type": "object",
+                    "properties": {},
+                    "required": []
+                }),
+            },
         ];
 
         // Add code_search tool
@@ -4352,6 +4361,46 @@ impl<W: UiWriter> Agent<W> {
                     Ok("❌ Missing content argument".to_string())
                 }
             }
+            "code_coverage" => {
+                debug!("Processing code_coverage tool call");
+                self.ui_writer.print_context_status("🔍 Generating code coverage report...");
+                
+                // Ensure coverage tools are installed
+                match g3_execution::ensure_coverage_tools_installed() {
+                    Ok(already_installed) => {
+                        if !already_installed {
+                            self.ui_writer.print_context_status("✅ Coverage tools installed successfully");
+                        }
+                    }
+                    Err(e) => {
+                        return Ok(format!("❌ Failed to install coverage tools: {}", e));
+                    }
+                }
+                
+                // Run cargo llvm-cov --workspace
+                let output = std::process::Command::new("cargo")
+                    .args(&["llvm-cov", "--workspace"])
+                    .current_dir(std::env::current_dir()?)
+                    .output()?;
+                
+                if output.status.success() {
+                    let stdout = String::from_utf8_lossy(&output.stdout);
+                    let stderr = String::from_utf8_lossy(&output.stderr);
+                    
+                    // Combine output
+                    let mut result = String::from("✅ Code coverage report generated successfully\n\n");
+                    result.push_str("## Coverage Summary\n");
+                    result.push_str(&stdout);
+                    if !stderr.is_empty() {
+                        result.push_str("\n## Warnings\n");
+                        result.push_str(&stderr);
+                    }
+                    Ok(result)
+                } else {
+                    let stderr = String::from_utf8_lossy(&output.stderr);
+                    Ok(format!("❌ Failed to generate coverage report:\n{}", stderr))
+                }
+            }
             "webdriver_start" => {
                 debug!("Processing webdriver_start tool call");
 

crates/g3-execution/examples/setup_coverage_tools.rs

@@ -0,0 +1,13 @@
+use g3_execution::ensure_coverage_tools_installed;
+
+fn main() -> anyhow::Result<()> {
+    // Ensure coverage tools are installed
+    let already_installed = ensure_coverage_tools_installed()?;
+    
+    if already_installed {
+        println!("All coverage tools are already installed!");
+    } else {
+        println!("Coverage tools have been installed successfully!");
+    }
+    Ok(())
+}

crates/g3-execution/src/lib.rs

@@ -330,3 +330,87 @@ impl CodeExecutor {
         })
     }
 }
+
+/// Check if rustup component llvm-tools-preview is installed
+pub fn is_llvm_tools_installed() -> Result<bool> {
+    let output = Command::new("rustup")
+        .args(&["component", "list", "--installed"])
+        .output()?;
+    
+    let installed = String::from_utf8_lossy(&output.stdout)
+        .lines()
+        .any(|line| line.trim() == "llvm-tools-preview" || line.starts_with("llvm-tools"));
+    
+    Ok(installed)
+}
+
+/// Check if cargo-llvm-cov is installed
+pub fn is_cargo_llvm_cov_installed() -> Result<bool> {
+    let output = Command::new("cargo")
+        .args(&["--list"])
+        .output()?;
+    
+    let installed = String::from_utf8_lossy(&output.stdout)
+        .lines()
+        .any(|line| line.trim().starts_with("llvm-cov"));
+    
+    Ok(installed)
+}
+
+/// Install llvm-tools-preview via rustup
+pub fn install_llvm_tools() -> Result<()> {
+    info!("Installing llvm-tools-preview...");
+    let output = Command::new("rustup")
+        .args(&["component", "add", "llvm-tools-preview"])
+        .output()?;
+    
+    if !output.status.success() {
+        let stderr = String::from_utf8_lossy(&output.stderr);
+        anyhow::bail!("Failed to install llvm-tools-preview: {}", stderr);
+    }
+    
+    info!("✅ llvm-tools-preview installed successfully");
+    Ok(())
+}
+
+/// Install cargo-llvm-cov via cargo install
+pub fn install_cargo_llvm_cov() -> Result<()> {
+    info!("Installing cargo-llvm-cov... (this may take a few minutes)");
+    let output = Command::new("cargo")
+        .args(&["install", "cargo-llvm-cov"])
+        .output()?;
+    
+    if !output.status.success() {
+        let stderr = String::from_utf8_lossy(&output.stderr);
+        anyhow::bail!("Failed to install cargo-llvm-cov: {}", stderr);
+    }
+    
+    info!("✅ cargo-llvm-cov installed successfully");
+    Ok(())
+}
+
+/// Ensure both llvm-tools-preview and cargo-llvm-cov are installed
+/// Returns Ok(true) if tools were already installed, Ok(false) if they were installed by this function
+pub fn ensure_coverage_tools_installed() -> Result<bool> {
+    let mut already_installed = true;
+    
+    // Check and install llvm-tools-preview
+    if !is_llvm_tools_installed()? {
+        info!("llvm-tools-preview not found, installing...");
+        install_llvm_tools()?;
+        already_installed = false;
+    } else {
+        info!("✅ llvm-tools-preview is already installed");
+    }
+    
+    // Check and install cargo-llvm-cov
+    if !is_cargo_llvm_cov_installed()? {
+        info!("cargo-llvm-cov not found, installing...");
+        install_cargo_llvm_cov()?;
+        already_installed = false;
+    } else {
+        info!("✅ cargo-llvm-cov is already installed");
+    }
+    
+    Ok(already_installed)
+}