add code exploration fast start

This tries to short-circuit multiple round-trips to llm for reading code.
It's a precursor to trying to context engineer tailored to specific tasks.
In initial experiments, it's only marginally faster than regular mode, and burns more tokens.

Cargo.lock

@@ -1365,6 +1365,8 @@ dependencies = [
  "dirs 5.0.1",
  "g3-config",
  "g3-core",
+ "g3-planner",
+ "g3-providers",
  "hex",
  "indicatif",
  "ratatui",
@@ -1499,6 +1501,18 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "g3-planner"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "const_format",
+ "g3-providers",
+ "serde",
+ "serde_json",
+ "tokio",
+]
+
 [[package]]
 name = "g3-providers"
 version = "0.1.0"

Cargo.toml

@@ -2,6 +2,7 @@
 members = [
     "crates/g3-cli",
     "crates/g3-core", 
+    "crates/g3-planner",
     "crates/g3-providers",
     "crates/g3-config",
     "crates/g3-execution",

crates/g3-cli/Cargo.toml

@@ -7,6 +7,8 @@ description = "CLI interface for G3 AI coding agent"
 [dependencies]
 g3-core = { path = "../g3-core" }
 g3-config = { path = "../g3-config" }
+g3-planner = { path = "../g3-planner" }
+g3-providers = { path = "../g3-providers" }
 clap = { workspace = true }
 tokio = { workspace = true }
 anyhow = { workspace = true }

crates/g3-cli/src/lib.rs

@@ -159,7 +159,7 @@ fn extract_coach_feedback_from_logs(
 
 use clap::Parser;
 use g3_config::Config;
-use g3_core::{project::Project, ui_writer::UiWriter, Agent};
+use g3_core::{project::Project, ui_writer::UiWriter, Agent, DiscoveryOptions};
 use rustyline::error::ReadlineError;
 use rustyline::DefaultEditor;
 use std::path::Path;
@@ -247,6 +247,10 @@ pub struct Cli {
     /// Enable WebDriver browser automation tools
     #[arg(long)]
     pub webdriver: bool,
+
+    /// Enable fast codebase discovery before first LLM turn
+    #[arg(long, value_name = "PATH")]
+    pub codebase_fast_start: Option<PathBuf>,
 }
 
 pub async fn run() -> Result<()> {
@@ -676,6 +680,7 @@ async fn run_accumulative_mode(
                     cli.show_code,
                     cli.max_turns,
                     cli.quiet,
+                    cli.codebase_fast_start.clone(),
                     ) => result,
                     _ = tokio::signal::ctrl_c() => {
                         output.print("\n⚠️  Autonomous run cancelled by user (Ctrl+C)");
@@ -727,6 +732,7 @@ async fn run_autonomous_machine(
     show_code: bool,
     max_turns: usize,
     _quiet: bool,
+    _codebase_fast_start: Option<PathBuf>,
 ) -> Result<()> {
     println!("AUTONOMOUS_MODE_STARTED");
     println!("WORKSPACE: {}", project.workspace().display());
@@ -757,7 +763,7 @@ async fn run_autonomous_machine(
     );
 
     println!("TASK_START");
-    let result = agent.execute_task_with_timing(&task, None, false, show_prompt, show_code, true).await?;
+    let result = agent.execute_task_with_timing(&task, None, false, show_prompt, show_code, true, None).await?;
     println!("AGENT_RESPONSE:");
     println!("{}", result.response);
     println!("END_AGENT_RESPONSE");
@@ -784,13 +790,14 @@ async fn run_with_console_mode(
             cli.show_code,
             cli.max_turns,
             cli.quiet,
+            cli.codebase_fast_start.clone(),
         )
         .await?;
     } else if let Some(task) = cli.task {
         // Single-shot mode
         let output = SimpleOutput::new();
         let result = agent
-            .execute_task_with_timing(&task, None, false, cli.show_prompt, cli.show_code, true)
+            .execute_task_with_timing(&task, None, false, cli.show_prompt, cli.show_code, true, None)
             .await?;
         output.print_smart(&result.response);
     } else {
@@ -815,12 +822,13 @@ async fn run_with_machine_mode(
             cli.show_code,
             cli.max_turns,
             cli.quiet,
+            cli.codebase_fast_start.clone(),
         )
         .await?;
     } else if let Some(task) = cli.task {
         // Single-shot mode
         let result = agent
-            .execute_task_with_timing(&task, None, false, cli.show_prompt, cli.show_code, true)
+            .execute_task_with_timing(&task, None, false, cli.show_prompt, cli.show_code, true, None)
             .await?;
         println!("AGENT_RESPONSE:");
         println!("{}", result.response);
@@ -1212,7 +1220,7 @@ async fn execute_task<W: UiWriter>(
         // Execute task with cancellation support
         let execution_result = tokio::select! {
             result = agent.execute_task_with_timing_cancellable(
-                input, None, false, show_prompt, show_code, true, cancellation_token.clone()
+                input, None, false, show_prompt, show_code, true, cancellation_token.clone(), None
             ) => {
                 result
             }
@@ -1403,7 +1411,7 @@ async fn execute_task_machine(
         // Execute task with cancellation support
         let execution_result = tokio::select! {
             result = agent.execute_task_with_timing_cancellable(
-                input, None, false, show_prompt, show_code, true, cancellation_token.clone()
+                input, None, false, show_prompt, show_code, true, cancellation_token.clone(), None
             ) => {
                 result
             }
@@ -1552,6 +1560,7 @@ async fn run_autonomous(
     show_code: bool,
     max_turns: usize,
     quiet: bool,
+    codebase_fast_start: Option<PathBuf>,
 ) -> Result<()> {
     let start_time = std::time::Instant::now();
     let output = SimpleOutput::new();
@@ -1684,6 +1693,39 @@ async fn run_autonomous(
         output.print("🎯 Starting with player implementation");
     }
 
+    // Load fast-discovery messages before the loop starts (if enabled)
+    let (discovery_messages, discovery_working_dir): (Vec<g3_providers::Message>, Option<String>) = 
+    if let Some(ref codebase_path) = codebase_fast_start {
+        // Canonicalize the path to ensure it's absolute
+        let canonical_path = codebase_path.canonicalize().unwrap_or_else(|_| codebase_path.clone());
+        let path_str = canonical_path.to_string_lossy();
+        output.print(&format!("🔍 Fast-discovery mode: will explore codebase at {}", path_str));
+        // Get the provider from the agent and use async LLM-based discovery
+        match agent.get_provider() {
+            Ok(provider) => {
+                // Create a status callback that prints to output
+                let output_clone = output.clone();
+                let status_callback: g3_planner::StatusCallback = Box::new(move |msg: &str| {
+                    output_clone.print(msg);
+                });
+                match g3_planner::get_initial_discovery_messages(&path_str, provider, Some(&status_callback)).await {
+                    Ok(messages) => (messages, Some(path_str.to_string())),
+                    Err(e) => {
+                        output.print(&format!("⚠️ LLM discovery failed: {}, skipping fast-start", e));
+                        (Vec::new(), None)
+                    }
+                }
+            }
+            Err(e) => {
+                output.print(&format!("⚠️ Could not get provider: {}, skipping fast-start", e));
+                (Vec::new(), None)
+            }
+        }
+    } else {
+        (Vec::new(), None)
+    };
+    let has_discovery = !discovery_messages.is_empty();
+
     let mut turn = 1;
     let mut coach_feedback = String::new();
     let mut implementation_approved = false;
@@ -1749,6 +1791,12 @@ async fn run_autonomous(
                         show_prompt,
                         show_code,
                         true,
+                        if has_discovery {
+                            Some(DiscoveryOptions {
+                                messages: &discovery_messages,
+                                fast_start_path: discovery_working_dir.as_deref(),
+                            })
+                        } else { None },
                     )
                     .await
                 {
@@ -1946,7 +1994,13 @@ Remember: Be clear in your review and concise in your feedback. APPROVE iff the
 
         loop {
             match coach_agent
-                .execute_task_with_timing(&coach_prompt, None, false, show_prompt, show_code, true)
+                .execute_task_with_timing(&coach_prompt, None, false, show_prompt, show_code, true, 
+                    if has_discovery {
+                        Some(DiscoveryOptions {
+                            messages: &discovery_messages,
+                            fast_start_path: discovery_working_dir.as_deref(),
+                        })
+                    } else { None })
                 .await
             {
                 Ok(result) => {

crates/g3-cli/src/simple_output.rs

@@ -1,4 +1,5 @@
 /// Simple output helper for printing messages
+#[derive(Clone)]
 pub struct SimpleOutput {
     machine_mode: bool,
 }

crates/g3-core/src/lib.rs

@@ -46,6 +46,13 @@ pub struct ToolCall {
     pub args: serde_json::Value, // Should be a JSON object with tool-specific arguments
 }
 
+/// Options for fast-start discovery execution
+#[derive(Debug, Clone)]
+pub struct DiscoveryOptions<'a> {
+    pub messages: &'a [Message],
+    pub fast_start_path: Option<&'a str>,
+}
+
 #[derive(Debug, Clone)]
 pub enum StreamState {
     Generating,
@@ -760,6 +767,8 @@ pub struct Agent<W: UiWriter> {
         std::sync::Arc<tokio::sync::RwLock<Option<g3_computer_control::MacAxController>>>,
     tool_call_count: usize,
     requirements_sha: Option<String>,
+    /// Working directory for tool execution (set by --codebase-fast-start)
+    working_dir: Option<String>,
 }
 
 impl<W: UiWriter> Agent<W> {
@@ -1032,6 +1041,7 @@ impl<W: UiWriter> Agent<W> {
             },
             tool_call_count: 0,
             requirements_sha: None,
+            working_dir: None,
         })
     }
 
@@ -1282,6 +1292,11 @@ impl<W: UiWriter> Agent<W> {
         Ok((provider.name().to_string(), provider.model().to_string()))
     }
 
+    /// Get the default LLM provider
+    pub fn get_provider(&self) -> Result<&dyn g3_providers::LLMProvider> {
+        self.providers.get(None)
+    }
+
     /// Get the current session ID for this agent
     pub fn get_session_id(&self) -> Option<&str> {
         self.session_id.as_deref()
@@ -1293,7 +1308,7 @@ impl<W: UiWriter> Agent<W> {
         language: Option<&str>,
         _auto_execute: bool,
     ) -> Result<TaskResult> {
-        self.execute_task_with_options(description, language, false, false, false)
+        self.execute_task_with_options(description, language, false, false, false, None)
             .await
     }
 
@@ -1304,6 +1319,7 @@ impl<W: UiWriter> Agent<W> {
         _auto_execute: bool,
         show_prompt: bool,
         show_code: bool,
+        discovery_options: Option<DiscoveryOptions<'_>>,
     ) -> Result<TaskResult> {
         self.execute_task_with_timing(
             description,
@@ -1312,6 +1328,7 @@ impl<W: UiWriter> Agent<W> {
             show_prompt,
             show_code,
             false,
+            discovery_options,
         )
         .await
     }
@@ -1324,6 +1341,7 @@ impl<W: UiWriter> Agent<W> {
         show_prompt: bool,
         show_code: bool,
         show_timing: bool,
+        discovery_options: Option<DiscoveryOptions<'_>>,
     ) -> Result<TaskResult> {
         // Create a cancellation token that never cancels for backward compatibility
         let cancellation_token = CancellationToken::new();
@@ -1335,6 +1353,7 @@ impl<W: UiWriter> Agent<W> {
             show_code,
             show_timing,
             cancellation_token,
+            discovery_options,
         )
         .await
     }
@@ -1349,6 +1368,7 @@ impl<W: UiWriter> Agent<W> {
         show_code: bool,
         show_timing: bool,
         cancellation_token: CancellationToken,
+        discovery_options: Option<DiscoveryOptions<'_>>,
     ) -> Result<TaskResult> {
         // Execute the task directly without splitting
         self.execute_single_task(
@@ -1357,6 +1377,7 @@ impl<W: UiWriter> Agent<W> {
             show_code,
             show_timing,
             cancellation_token,
+            discovery_options,
         )
         .await
     }
@@ -1368,6 +1389,7 @@ impl<W: UiWriter> Agent<W> {
         _show_code: bool,
         show_timing: bool,
         cancellation_token: CancellationToken,
+        discovery_options: Option<DiscoveryOptions<'_>>,
     ) -> Result<TaskResult> {
         // Reset the JSON tool call filter state at the start of each new task
         // This prevents the filter from staying in suppression mode between user interactions
@@ -1385,6 +1407,39 @@ impl<W: UiWriter> Agent<W> {
         let user_message = Message::new(MessageRole::User, format!("Task: {}", description));
         self.context_window.add_message(user_message);
 
+        // Execute fast-discovery tool calls if provided (immediately after user message)
+        if let Some(ref options) = discovery_options {
+            self.ui_writer.println("▶️  Playing back discovery commands...");
+            // Store the working directory for subsequent tool calls in the streaming loop
+            if let Some(path) = options.fast_start_path {
+                self.working_dir = Some(path.to_string());
+            }
+            let provider = self.providers.get(None)?;
+            let supports_cache = provider.supports_cache_control();
+            let message_count = options.messages.len();
+            
+            for (idx, discovery_msg) in options.messages.iter().enumerate() {
+                if let Ok(tool_call) = serde_json::from_str::<ToolCall>(&discovery_msg.content) {
+                    self.add_message_to_context(discovery_msg.clone());
+                    let result = self.execute_tool_call_in_dir(&tool_call, options.fast_start_path).await
+                        .unwrap_or_else(|e| format!("Error: {}", e));
+                    
+                    // Add cache_control to the last user message if provider supports it (anthropic)
+                    let is_last = idx == message_count - 1;
+                    let result_message = if is_last && supports_cache {
+                        Message::with_cache_control(
+                            MessageRole::User,
+                            format!("Tool result: {}", result),
+                            CacheControl::ephemeral(),
+                        )
+                    } else {
+                        Message::new(MessageRole::User, format!("Tool result: {}", result))
+                    };
+                    self.add_message_to_context(result_message);
+                }
+            }
+        }
+
         // Use the complete conversation history for the request
         let messages = self.context_window.conversation_history.clone();
 
@@ -1575,6 +1630,24 @@ impl<W: UiWriter> Agent<W> {
         &self.context_window
     }
 
+    /// Add a message directly to the context window.
+    /// Used for injecting discovery messages before the first LLM turn.
+    pub fn add_message_to_context(&mut self, message: Message) {
+        self.context_window.add_message(message);
+    }
+
+    /// Execute a tool call and return the result.
+    /// This is a public wrapper around execute_tool for use by external callers
+    /// like the planner's fast-discovery feature.
+    pub async fn execute_tool_call(&mut self, tool_call: &ToolCall) -> Result<String> {
+        self.execute_tool(tool_call).await
+    }
+
+    /// Execute a tool call with an optional working directory (for discovery commands)
+    pub async fn execute_tool_call_in_dir(&mut self, tool_call: &ToolCall, working_dir: Option<&str>) -> Result<String> {
+        self.execute_tool_in_dir(tool_call, working_dir).await
+    }
+
     /// Log an error message to the session JSON file as the last message
     /// This is used in autonomous mode to record context length exceeded errors
     pub fn log_error_to_session(
@@ -3157,11 +3230,14 @@ impl<W: UiWriter> Agent<W> {
                                 self.ui_writer.print_tool_output_header();
                             }
 
+                            // Clone working_dir to avoid borrow checker issues
+                            let working_dir = self.working_dir.clone();
                             let exec_start = Instant::now();
                             // Add 8-minute timeout for tool execution
                             let tool_result = match tokio::time::timeout(
                                 Duration::from_secs(8 * 60), // 8 minutes
-                                self.execute_tool(&tool_call),
+                                // Use working_dir if set (from --codebase-fast-start)
+                                self.execute_tool_in_dir(&tool_call, working_dir.as_deref()),
                             )
                             .await
                             {
@@ -3707,8 +3783,17 @@ impl<W: UiWriter> Agent<W> {
     pub async fn execute_tool(&mut self, tool_call: &ToolCall) -> Result<String> {
         // Increment tool call count
         self.tool_call_count += 1;
+        self.execute_tool_in_dir(tool_call, None).await
+    }
 
-        let result = self.execute_tool_inner(tool_call).await;
+    /// Execute a tool with an optional working directory (for discovery commands)
+    pub async fn execute_tool_in_dir(&mut self, tool_call: &ToolCall, working_dir: Option<&str>) -> Result<String> {
+        // Only increment tool call count if not already incremented by execute_tool
+        if working_dir.is_some() {
+            self.tool_call_count += 1;
+        }
+
+        let result = self.execute_tool_inner_in_dir(tool_call, working_dir).await;
         let log_str = match &result {
             Ok(s) => s.clone(),
             Err(e) => format!("ERROR: {}", e),
@@ -3717,9 +3802,12 @@ impl<W: UiWriter> Agent<W> {
         result
     }
 
-    async fn execute_tool_inner(&mut self, tool_call: &ToolCall) -> Result<String> {
+    async fn execute_tool_inner_in_dir(&mut self, tool_call: &ToolCall, working_dir: Option<&str>) -> Result<String> {
         debug!("=== EXECUTING TOOL ===");
         debug!("Tool name: {}", tool_call.tool);
+        eprintln!("[DEBUG execute_tool_inner_in_dir] tool='{}' working_dir={:?} args={}", 
+            tool_call.tool, working_dir, serde_json::to_string(&tool_call.args).unwrap_or_default());
+        debug!("Working directory passed to execute_tool_inner_in_dir: {:?}", working_dir);
         debug!("Tool args (raw): {:?}", tool_call.args);
         debug!(
             "Tool args (JSON): {}",
@@ -3754,9 +3842,11 @@ impl<W: UiWriter> Agent<W> {
                         let receiver = ToolOutputReceiver {
                             ui_writer: &self.ui_writer,
                         };
+                        
+                        debug!("ABOUT TO CALL execute_bash_streaming_in_dir: escaped_command='{}', working_dir={:?}", escaped_command, working_dir);
 
                         match executor
-                            .execute_bash_streaming(&escaped_command, &receiver)
+                            .execute_bash_streaming_in_dir(&escaped_command, &receiver, working_dir)
                             .await
                         {
                             Ok(result) => {

crates/g3-execution/src/lib.rs

@@ -5,6 +5,17 @@ use tempfile::NamedTempFile;
 use std::io::Write;
 use tracing::{info, debug, error};
 
+/// Expand tilde (~) in a path to the user's home directory
+fn expand_tilde(path: &str) -> String {
+    if path.starts_with("~") {
+        if let Some(home) = std::env::var_os("HOME") {
+            let home_str = home.to_string_lossy();
+            return path.replacen("~", &home_str, 1);
+        }
+    }
+    path.to_string()
+}
+
 pub struct CodeExecutor {
     // Future: add configuration for execution limits, sandboxing, etc.
 }
@@ -241,11 +252,33 @@ impl CodeExecutor {
         &self, 
         code: &str, 
         receiver: &R
+    ) -> Result<ExecutionResult> {
+        self.execute_bash_streaming_in_dir(code, receiver, None).await
+    }
+
+    /// Execute bash command with streaming output in a specific directory
+    pub async fn execute_bash_streaming_in_dir<R: OutputReceiver>(
+        &self, 
+        code: &str, 
+        receiver: &R,
+        working_dir: Option<&str>,
     ) -> Result<ExecutionResult> {
         use std::process::Stdio;
         use tokio::io::{AsyncBufReadExt, BufReader};
         use tokio::process::Command as TokioCommand;
         
+        // CRITICAL DEBUG: Print to stderr so it's always visible
+        debug!("========== execute_bash_streaming_in_dir START ==========");
+        debug!("Code to execute: {}", code);
+        debug!("Working directory parameter: {:?}", working_dir);
+        debug!("FULL DIAGNOSTIC: code='{}', working_dir={:?}", code, working_dir);
+        
+        if let Some(dir) = working_dir {
+            debug!("Working dir exists check: {}", std::path::Path::new(dir).exists());
+            debug!("Working dir is_dir check: {}", std::path::Path::new(dir).is_dir());
+        }
+        debug!("Current process working directory: {:?}", std::env::current_dir());
+        
         // Check if this is a detached/daemon command that should run independently
         // Look for patterns like: setsid, nohup with &, or explicit backgrounding with disown
         let is_detached = code.trim_start().starts_with("setsid ") 
@@ -255,10 +288,17 @@ impl CodeExecutor {
         
         if is_detached {
             // For detached commands, just spawn and return immediately
-            TokioCommand::new("bash")
+            let mut cmd = TokioCommand::new("bash");
-                .arg("-c")
+            cmd.arg("-c")
-                .arg(code)
+                .arg(code);
-                .spawn()?;
+            
+            // Set working directory if provided
+            if let Some(dir) = working_dir {
+                let expanded_dir = expand_tilde(dir);
+                cmd.current_dir(&expanded_dir);
+            }
+            
+            cmd.spawn()?;
             
             // Don't wait for the process - it's meant to run independently
             return Ok(ExecutionResult {
@@ -269,12 +309,33 @@ impl CodeExecutor {
             });
         }
         
-        let mut child = TokioCommand::new("bash")
+        let mut cmd = TokioCommand::new("bash");
-            .arg("-c")
+        cmd.arg("-c")
             .arg(code)
             .stdout(Stdio::piped())
-            .stderr(Stdio::piped())
+            .stderr(Stdio::piped());
-            .spawn()?;
+        
+        // Set working directory if provided
+        if let Some(dir) = working_dir {
+            debug!("Setting current_dir on command to: {}", dir);
+            let expanded_dir = expand_tilde(dir);
+            debug!("Expanded working dir: {}", expanded_dir);
+            debug!("Expanded dir exists: {}", std::path::Path::new(&expanded_dir).exists());
+            debug!("Expanded dir is_dir: {}", std::path::Path::new(&expanded_dir).is_dir());
+            cmd.current_dir(&expanded_dir);
+        }
+        
+        debug!("About to spawn command...");
+        let spawn_result = cmd.spawn();
+        debug!("Spawn result: {:?}", spawn_result.is_ok());
+        let mut child = match spawn_result {
+            Ok(c) => c,
+            Err(e) => {
+                debug!("SPAWN ERROR: {:?}", e);
+                return Err(e.into());
+            }
+        };
+        debug!("Command spawned successfully");
         
         let stdout = child.stdout.take().unwrap();
         let stderr = child.stderr.take().unwrap();
@@ -322,12 +383,23 @@ impl CodeExecutor {
         
         let status = child.wait().await?;
         
-        Ok(ExecutionResult {
+        let result = ExecutionResult {
             stdout: stdout_output.join("\n"),
             stderr: stderr_output.join("\n"),
             exit_code: status.code().unwrap_or(-1),
             success: status.success(),
-        })
+        };
+        
+        debug!("========== execute_bash_streaming_in_dir END ==========");
+        debug!("Exit code: {}", result.exit_code);
+        debug!("Success: {}", result.success);
+        debug!("Stdout length: {}", result.stdout.len());
+        debug!("Stderr length: {}", result.stderr.len());
+        if !result.stderr.is_empty() {
+            debug!("Stderr content: {}", result.stderr);
+        }
+
+        Ok(result)
     }
 }
 

crates/g3-planner/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "g3-planner"
+version = "0.1.0"
+edition = "2021"
+description = "Fast-discovery planner for G3 AI coding agent"
+
+[dependencies]
+g3-providers = { path = "../g3-providers" }
+serde = { workspace = true }
+serde_json = { workspace = true }
+const_format = "0.2"
+anyhow = { workspace = true }
+tokio = { workspace = true }

crates/g3-planner/src/code_explore.rs

@@ -0,0 +1,724 @@
+//! Code exploration module for analyzing codebases
+//!
+//! This module provides functions to explore and analyze codebases
+//! for various programming languages, returning structured reports
+//! about the code structure.
+
+use std::path::Path;
+use std::process::Command;
+
+/// Main entry point for exploring a codebase at the given path.
+/// Detects which languages are present and generates a comprehensive report.
+pub fn explore_codebase(path: &str) -> String {
+    let path = expand_tilde(path);
+    let mut report = String::new();
+    let mut languages_found = Vec::new();
+
+    // Check for each language and add to report if found
+    if has_rust_files(&path) {
+        languages_found.push("Rust".to_string());
+        report.push_str(&explore_rust(&path));
+    }
+    if has_java_files(&path) {
+        languages_found.push("Java".to_string());
+        report.push_str(&explore_java(&path));
+    }
+    if has_kotlin_files(&path) {
+        languages_found.push("Kotlin".to_string());
+        report.push_str(&explore_kotlin(&path));
+    }
+    if has_swift_files(&path) {
+        languages_found.push("Swift".to_string());
+        report.push_str(&explore_swift(&path));
+    }
+    if has_go_files(&path) {
+        languages_found.push("Go".to_string());
+        report.push_str(&explore_go(&path));
+    }
+    if has_python_files(&path) {
+        languages_found.push("Python".to_string());
+        report.push_str(&explore_python(&path));
+    }
+    if has_typescript_files(&path) {
+        languages_found.push("TypeScript".to_string());
+        report.push_str(&explore_typescript(&path));
+    }
+    if has_javascript_files(&path) {
+        languages_found.push("JavaScript".to_string());
+        report.push_str(&explore_javascript(&path));
+    }
+    if has_cpp_files(&path) {
+        languages_found.push("C/C++".to_string());
+        report.push_str(&explore_cpp(&path));
+    }
+    if has_markdown_files(&path) {
+        languages_found.push("Markdown".to_string());
+        report.push_str(&explore_markdown(&path));
+    }
+    if has_yaml_files(&path) {
+        languages_found.push("YAML".to_string());
+        report.push_str(&explore_yaml(&path));
+    }
+    if has_sql_files(&path) {
+        languages_found.push("SQL".to_string());
+        report.push_str(&explore_sql(&path));
+    }
+    if has_ruby_files(&path) {
+        languages_found.push("Ruby".to_string());
+        report.push_str(&explore_ruby(&path));
+    }
+
+    if languages_found.is_empty() {
+        report.push_str("No recognized programming languages found in the codebase.\n");
+    } else {
+        let header = format!(
+            "=== CODEBASE ANALYSIS ===\nLanguages detected: {}\n\n",
+            languages_found.join(", ")
+        );
+        report = header + &report;
+    }
+
+    report
+}
+
+/// Expand tilde to home directory
+fn expand_tilde(path: &str) -> String {
+    if path.starts_with("~/") {
+        if let Some(home) = std::env::var_os("HOME") {
+            return path.replacen("~", &home.to_string_lossy(), 1);
+        }
+    }
+    path.to_string()
+}
+
+/// Run a shell command and return its output
+fn run_command(cmd: &str, working_dir: &str) -> String {
+    let output = Command::new("sh")
+        .arg("-c")
+        .arg(cmd)
+        .current_dir(working_dir)
+        .output();
+
+    match output {
+        Ok(out) => {
+            let stdout = String::from_utf8_lossy(&out.stdout);
+            let stderr = String::from_utf8_lossy(&out.stderr);
+            if !stdout.is_empty() {
+                stdout.to_string()
+            } else if !stderr.is_empty() {
+                format!("(stderr): {}", stderr)
+            } else {
+                String::new()
+            }
+        }
+        Err(e) => format!("Error running command: {}", e),
+    }
+}
+
+/// Check if files with given extension exist
+fn has_files_with_extension(path: &str, extension: &str) -> bool {
+    let cmd = format!(
+        "find . -name '.git' -prune -o -type f -name '*.{}' -print | head -1",
+        extension
+    );
+    !run_command(&cmd, path).trim().is_empty()
+}
+
+// Language detection functions
+fn has_rust_files(path: &str) -> bool {
+    has_files_with_extension(path, "rs") || Path::new(path).join("Cargo.toml").exists()
+}
+
+fn has_java_files(path: &str) -> bool {
+    has_files_with_extension(path, "java")
+}
+
+fn has_kotlin_files(path: &str) -> bool {
+    has_files_with_extension(path, "kt") || has_files_with_extension(path, "kts")
+}
+
+fn has_swift_files(path: &str) -> bool {
+    has_files_with_extension(path, "swift")
+}
+
+fn has_go_files(path: &str) -> bool {
+    has_files_with_extension(path, "go")
+}
+
+fn has_python_files(path: &str) -> bool {
+    has_files_with_extension(path, "py")
+}
+
+fn has_typescript_files(path: &str) -> bool {
+    has_files_with_extension(path, "ts") || has_files_with_extension(path, "tsx")
+}
+
+fn has_javascript_files(path: &str) -> bool {
+    has_files_with_extension(path, "js") || has_files_with_extension(path, "jsx")
+}
+
+fn has_cpp_files(path: &str) -> bool {
+    has_files_with_extension(path, "cpp")
+        || has_files_with_extension(path, "cc")
+        || has_files_with_extension(path, "c")
+        || has_files_with_extension(path, "h")
+        || has_files_with_extension(path, "hpp")
+}
+
+fn has_markdown_files(path: &str) -> bool {
+    has_files_with_extension(path, "md")
+}
+
+fn has_yaml_files(path: &str) -> bool {
+    has_files_with_extension(path, "yaml") || has_files_with_extension(path, "yml")
+}
+
+fn has_sql_files(path: &str) -> bool {
+    has_files_with_extension(path, "sql")
+}
+
+fn has_ruby_files(path: &str) -> bool {
+    has_files_with_extension(path, "rb")
+}
+
+/// Explore Rust codebase
+pub fn explore_rust(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== RUST ===\n\n");
+
+    // File structure
+    report.push_str("--- File Structure ---\n");
+    let files = run_command(
+        "rg --files -g '*.rs' . 2>/dev/null | grep -v '/target/' | sort | head -100",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // Dependencies (Cargo.toml)
+    report.push_str("--- Dependencies (Cargo.toml) ---\n");
+    let cargo = run_command("cat Cargo.toml 2>/dev/null | head -50", path);
+    report.push_str(&cargo);
+    report.push('\n');
+
+    // Data structures
+    report.push_str("--- Data Structures (Structs, Enums, Types) ---\n");
+    let structs = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.rs' '^(pub )?(struct|enum|type|union) ' . 2>/dev/null | grep -v '/target/' | head -100"#,
+        path,
+    );
+    report.push_str(&structs);
+    report.push('\n');
+
+    // Traits and implementations
+    report.push_str("--- Traits & Implementations ---\n");
+    let traits = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.rs' '^(pub )?trait |^impl ' . 2>/dev/null | grep -v '/target/' | head -100"#,
+        path,
+    );
+    report.push_str(&traits);
+    report.push('\n');
+
+    // Public functions
+    report.push_str("--- Public Functions ---\n");
+    let funcs = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.rs' '^pub (async )?fn ' . 2>/dev/null | grep -v '/target/' | head -100"#,
+        path,
+    );
+    report.push_str(&funcs);
+    report.push('\n');
+
+    report
+}
+
+/// Explore Java codebase
+pub fn explore_java(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== JAVA ===\n\n");
+
+    // File structure
+    report.push_str("--- File Structure ---\n");
+    let files = run_command(
+        "rg --files -g '*.java' . 2>/dev/null | grep -v '/build/' | grep -v '/target/' | sort | head -100",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // Build files
+    report.push_str("--- Build Configuration ---\n");
+    let build = run_command(
+        "cat pom.xml 2>/dev/null | head -50 || cat build.gradle 2>/dev/null | head -50",
+        path,
+    );
+    report.push_str(&build);
+    report.push('\n');
+
+    // Classes and interfaces
+    report.push_str("--- Classes & Interfaces ---\n");
+    let classes = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.java' '^(public |private |protected )?(abstract )?(class|interface|enum|record) ' . 2>/dev/null | grep -v '/build/' | head -100"#,
+        path,
+    );
+    report.push_str(&classes);
+    report.push('\n');
+
+    // Public methods
+    report.push_str("--- Public Methods ---\n");
+    let methods = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.java' '^\s+public .+\(' . 2>/dev/null | grep -v '/build/' | head -100"#,
+        path,
+    );
+    report.push_str(&methods);
+    report.push('\n');
+
+    report
+}
+
+/// Explore Kotlin codebase
+pub fn explore_kotlin(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== KOTLIN ===\n\n");
+
+    // File structure
+    report.push_str("--- File Structure ---\n");
+    let files = run_command(
+        "rg --files -g '*.kt' -g '*.kts' . 2>/dev/null | grep -v '/build/' | sort | head -100",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // Build files
+    report.push_str("--- Build Configuration ---\n");
+    let build = run_command("cat build.gradle.kts 2>/dev/null | head -50 || cat build.gradle 2>/dev/null | head -50", path);
+    report.push_str(&build);
+    report.push('\n');
+
+    // Classes, objects, interfaces
+    report.push_str("--- Classes, Objects & Interfaces ---\n");
+    let classes = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.kt' '^(data |sealed |open |abstract )?(class|interface|object|enum class) ' . 2>/dev/null | grep -v '/build/' | head -100"#,
+        path,
+    );
+    report.push_str(&classes);
+    report.push('\n');
+
+    // Functions
+    report.push_str("--- Functions ---\n");
+    let funcs = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.kt' '^(suspend |private |internal |public )?fun ' . 2>/dev/null | grep -v '/build/' | head -100"#,
+        path,
+    );
+    report.push_str(&funcs);
+    report.push('\n');
+
+    report
+}
+
+/// Explore Swift codebase
+pub fn explore_swift(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== SWIFT ===\n\n");
+
+    // File structure
+    report.push_str("--- File Structure ---\n");
+    let files = run_command(
+        "rg --files -g '*.swift' . 2>/dev/null | grep -v '/.build/' | sort | head -100",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // Package.swift
+    report.push_str("--- Package Configuration ---\n");
+    let pkg = run_command("cat Package.swift 2>/dev/null | head -50", path);
+    report.push_str(&pkg);
+    report.push('\n');
+
+    // Classes, structs, protocols
+    report.push_str("--- Types (Classes, Structs, Protocols, Enums) ---\n");
+    let types = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.swift' '^(public |private |internal |open |final )?(class|struct|protocol|enum|actor) ' . 2>/dev/null | grep -v '/.build/' | head -100"#,
+        path,
+    );
+    report.push_str(&types);
+    report.push('\n');
+
+    // Functions
+    report.push_str("--- Functions ---\n");
+    let funcs = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.swift' '^\s*(public |private |internal |open )?func ' . 2>/dev/null | grep -v '/.build/' | head -100"#,
+        path,
+    );
+    report.push_str(&funcs);
+    report.push('\n');
+
+    report
+}
+
+/// Explore Go codebase
+pub fn explore_go(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== GO ===\n\n");
+
+    // File structure
+    report.push_str("--- File Structure ---\n");
+    let files = run_command(
+        "rg --files -g '*.go' . 2>/dev/null | grep -v '/vendor/' | sort | head -100",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // go.mod
+    report.push_str("--- Module Configuration ---\n");
+    let gomod = run_command("cat go.mod 2>/dev/null | head -50", path);
+    report.push_str(&gomod);
+    report.push('\n');
+
+    // Types (structs, interfaces)
+    report.push_str("--- Types (Structs & Interfaces) ---\n");
+    let types = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.go' '^type .+ (struct|interface)' . 2>/dev/null | grep -v '/vendor/' | head -100"#,
+        path,
+    );
+    report.push_str(&types);
+    report.push('\n');
+
+    // Functions
+    report.push_str("--- Functions ---\n");
+    let funcs = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.go' '^func ' . 2>/dev/null | grep -v '/vendor/' | head -100"#,
+        path,
+    );
+    report.push_str(&funcs);
+    report.push('\n');
+
+    report
+}
+
+/// Explore Python codebase
+pub fn explore_python(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== PYTHON ===\n\n");
+
+    // File structure
+    report.push_str("--- File Structure ---\n");
+    let files = run_command(
+        "rg --files -g '*.py' . 2>/dev/null | grep -v '/__pycache__/' | grep -v '/venv/' | grep -v '/.venv/' | sort | head -100",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // Requirements/setup
+    report.push_str("--- Dependencies ---\n");
+    let deps = run_command(
+        "cat requirements.txt 2>/dev/null | head -30 || cat pyproject.toml 2>/dev/null | head -50 || cat setup.py 2>/dev/null | head -30",
+        path,
+    );
+    report.push_str(&deps);
+    report.push('\n');
+
+    // Classes
+    report.push_str("--- Classes ---\n");
+    let classes = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.py' '^class ' . 2>/dev/null | grep -v '/__pycache__/' | grep -v '/venv/' | head -100"#,
+        path,
+    );
+    report.push_str(&classes);
+    report.push('\n');
+
+    // Functions
+    report.push_str("--- Functions ---\n");
+    let funcs = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.py' '^def |^async def ' . 2>/dev/null | grep -v '/__pycache__/' | grep -v '/venv/' | head -100"#,
+        path,
+    );
+    report.push_str(&funcs);
+    report.push('\n');
+
+    report
+}
+
+/// Explore TypeScript codebase
+pub fn explore_typescript(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== TYPESCRIPT ===\n\n");
+
+    // File structure
+    report.push_str("--- File Structure ---\n");
+    let files = run_command(
+        "rg --files -g '*.ts' -g '*.tsx' . 2>/dev/null | grep -v '/node_modules/' | grep -v '/dist/' | sort | head -100",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // package.json
+    report.push_str("--- Package Configuration ---\n");
+    let pkg = run_command("cat package.json 2>/dev/null | head -50", path);
+    report.push_str(&pkg);
+    report.push('\n');
+
+    // Types, interfaces, classes
+    report.push_str("--- Types, Interfaces & Classes ---\n");
+    let types = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.ts' -g '*.tsx' '^export (type|interface|class|enum|abstract class) ' . 2>/dev/null | grep -v '/node_modules/' | head -100"#,
+        path,
+    );
+    report.push_str(&types);
+    report.push('\n');
+
+    // Functions
+    report.push_str("--- Exported Functions ---\n");
+    let funcs = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.ts' -g '*.tsx' '^export (async )?function |^export const .+ = (async )?\(' . 2>/dev/null | grep -v '/node_modules/' | head -100"#,
+        path,
+    );
+    report.push_str(&funcs);
+    report.push('\n');
+
+    report
+}
+
+/// Explore JavaScript codebase
+pub fn explore_javascript(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== JAVASCRIPT ===\n\n");
+
+    // File structure
+    report.push_str("--- File Structure ---\n");
+    let files = run_command(
+        "rg --files -g '*.js' -g '*.jsx' . 2>/dev/null | grep -v '/node_modules/' | grep -v '/dist/' | sort | head -100",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // package.json
+    report.push_str("--- Package Configuration ---\n");
+    let pkg = run_command("cat package.json 2>/dev/null | head -50", path);
+    report.push_str(&pkg);
+    report.push('\n');
+
+    // Classes
+    report.push_str("--- Classes ---\n");
+    let classes = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.js' -g '*.jsx' '^(export )?(default )?(class ) ' . 2>/dev/null | grep -v '/node_modules/' | head -100"#,
+        path,
+    );
+    report.push_str(&classes);
+    report.push('\n');
+
+    // Functions
+    report.push_str("--- Exported Functions ---\n");
+    let funcs = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.js' -g '*.jsx' '^(export )?(async )?function |^module\.exports' . 2>/dev/null | grep -v '/node_modules/' | head -100"#,
+        path,
+    );
+    report.push_str(&funcs);
+    report.push('\n');
+
+    report
+}
+
+/// Explore C/C++ codebase
+pub fn explore_cpp(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== C/C++ ===\n\n");
+
+    // File structure
+    report.push_str("--- File Structure ---\n");
+    let files = run_command(
+        "rg --files -g '*.c' -g '*.cpp' -g '*.cc' -g '*.h' -g '*.hpp' . 2>/dev/null | grep -v '/build/' | sort | head -100",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // Build files
+    report.push_str("--- Build Configuration ---\n");
+    let build = run_command(
+        "cat CMakeLists.txt 2>/dev/null | head -50 || cat Makefile 2>/dev/null | head -50",
+        path,
+    );
+    report.push_str(&build);
+    report.push('\n');
+
+    // Classes and structs
+    report.push_str("--- Classes & Structs ---\n");
+    let classes = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.cpp' -g '*.cc' -g '*.h' -g '*.hpp' '^(class|struct|enum|union|typedef) ' . 2>/dev/null | grep -v '/build/' | head -100"#,
+        path,
+    );
+    report.push_str(&classes);
+    report.push('\n');
+
+    // Functions (simplified pattern)
+    report.push_str("--- Function Declarations ---\n");
+    let funcs = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.h' -g '*.hpp' '^[a-zA-Z_][a-zA-Z0-9_<>: ]*\s+[a-zA-Z_][a-zA-Z0-9_]*\s*\(' . 2>/dev/null | grep -v '/build/' | head -100"#,
+        path,
+    );
+    report.push_str(&funcs);
+    report.push('\n');
+
+    report
+}
+
+/// Explore Markdown documentation
+pub fn explore_markdown(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== MARKDOWN DOCUMENTATION ===\n\n");
+
+    // File structure
+    report.push_str("--- Documentation Files ---\n");
+    let files = run_command(
+        "rg --files -g '*.md' . 2>/dev/null | grep -v '/node_modules/' | grep -v '/vendor/' | sort | head -50",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // README content
+    report.push_str("--- README Overview ---\n");
+    let readme = run_command(
+        "cat README.md 2>/dev/null | head -100 || cat readme.md 2>/dev/null | head -100",
+        path,
+    );
+    report.push_str(&readme);
+    report.push('\n');
+
+    // Headers from all markdown files
+    report.push_str("--- Document Headers ---\n");
+    let headers = run_command(
+        r#"rg --no-heading --line-number --with-filename -g '*.md' '^#{1,3} ' . 2>/dev/null | grep -v '/node_modules/' | head -100"#,
+        path,
+    );
+    report.push_str(&headers);
+    report.push('\n');
+
+    report
+}
+
+/// Explore YAML configuration files
+pub fn explore_yaml(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== YAML CONFIGURATION ===\n\n");
+
+    // File structure
+    report.push_str("--- YAML Files ---\n");
+    let files = run_command(
+        "rg --files -g '*.yaml' -g '*.yml' . 2>/dev/null | grep -v '/node_modules/' | grep -v '/vendor/' | sort | head -50",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // Top-level keys from YAML files
+    report.push_str("--- Top-Level Keys ---\n");
+    let keys = run_command(
+        r#"rg --no-heading --line-number --with-filename -g '*.yaml' -g '*.yml' '^[a-zA-Z_][a-zA-Z0-9_-]*:' . 2>/dev/null | grep -v '/node_modules/' | head -100"#,
+        path,
+    );
+    report.push_str(&keys);
+    report.push('\n');
+
+    report
+}
+
+/// Explore SQL files
+pub fn explore_sql(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== SQL ===\n\n");
+
+    // File structure
+    report.push_str("--- SQL Files ---\n");
+    let files = run_command(
+        "rg --files -g '*.sql' . 2>/dev/null | sort | head -50",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // Tables
+    report.push_str("--- Table Definitions ---\n");
+    let tables = run_command(
+        r#"rg --no-heading --line-number --with-filename -i -g '*.sql' 'CREATE TABLE' . 2>/dev/null | head -100"#,
+        path,
+    );
+    report.push_str(&tables);
+    report.push('\n');
+
+    // Views and procedures
+    report.push_str("--- Views & Procedures ---\n");
+    let views = run_command(
+        r#"rg --no-heading --line-number --with-filename -i -g '*.sql' 'CREATE (VIEW|PROCEDURE|FUNCTION)' . 2>/dev/null | head -100"#,
+        path,
+    );
+    report.push_str(&views);
+    report.push('\n');
+
+    report
+}
+
+/// Explore Ruby codebase
+pub fn explore_ruby(path: &str) -> String {
+    let mut report = String::new();
+    report.push_str("\n=== RUBY ===\n\n");
+
+    // File structure
+    report.push_str("--- File Structure ---\n");
+    let files = run_command(
+        "rg --files -g '*.rb' . 2>/dev/null | grep -v '/vendor/' | sort | head -100",
+        path,
+    );
+    report.push_str(&files);
+    report.push('\n');
+
+    // Gemfile
+    report.push_str("--- Dependencies (Gemfile) ---\n");
+    let gemfile = run_command("cat Gemfile 2>/dev/null | head -50", path);
+    report.push_str(&gemfile);
+    report.push('\n');
+
+    // Classes and modules
+    report.push_str("--- Classes & Modules ---\n");
+    let classes = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.rb' '^(class|module) ' . 2>/dev/null | grep -v '/vendor/' | head -100"#,
+        path,
+    );
+    report.push_str(&classes);
+    report.push('\n');
+
+    // Methods
+    report.push_str("--- Methods ---\n");
+    let methods = run_command(
+        r#"rg --no-heading --line-number --with-filename --max-filesize 500K -g '*.rb' '^\s*def ' . 2>/dev/null | grep -v '/vendor/' | head -100"#,
+        path,
+    );
+    report.push_str(&methods);
+    report.push('\n');
+
+    report
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_expand_tilde() {
+        let path = expand_tilde("~/test");
+        assert!(!path.starts_with("~"));
+    }
+
+    #[test]
+    fn test_explore_codebase_returns_string() {
+        // Test with current directory
+        let result = explore_codebase(".");
+        assert!(!result.is_empty());
+    }
+}

crates/g3-planner/src/lib.rs

@@ -0,0 +1,253 @@
+//! g3-planner: Fast-discovery planner for G3 AI coding agent
+//!
+//! This crate provides functionality to generate initial discovery tool calls
+//! that are injected into the conversation before the first LLM turn.
+
+mod code_explore;
+pub mod prompts;
+
+pub use code_explore::explore_codebase;
+
+use anyhow::Result;
+use g3_providers::{CompletionRequest, LLMProvider, Message, MessageRole};
+use prompts::{DISCOVERY_REQUIREMENTS_PROMPT, DISCOVERY_SYSTEM_PROMPT};
+
+/// Type alias for a status callback function
+pub type StatusCallback = Box<dyn Fn(&str) + Send + Sync>;
+
+/// Generates initial discovery messages for fast codebase exploration.
+///
+/// This function:
+/// 1. Runs explore_codebase to get a codebase report
+/// 2. Sends the report to the LLM with DISCOVERY_SYSTEM_PROMPT
+/// 3. Extracts shell commands from the LLM response
+/// 4. Returns Assistant messages with tool calls for each command
+///
+/// # Arguments
+///
+/// * `codebase_path` - The path to the codebase to explore
+/// * `provider` - An LLM provider to query for exploration commands
+/// * `status_callback` - Optional callback for status updates
+///
+/// # Returns
+///
+/// A `Result<Vec<Message>>` containing Assistant messages with JSON tool call strings.
+pub async fn get_initial_discovery_messages(
+    codebase_path: &str,
+    provider: &dyn LLMProvider,
+    status_callback: Option<&StatusCallback>,
+) -> Result<Vec<Message>> {
+    // Helper to call status callback if provided
+    let status = |msg: &str| {
+        if let Some(cb) = status_callback {
+            cb(msg);
+        }
+    };
+
+    status("🔍 Starting code discovery...");
+
+    // Step 1: Run explore_codebase to get the codebase report
+    let codebase_report = explore_codebase(codebase_path);
+
+    // Step 2: Build the prompt with the codebase report appended
+    let user_prompt = format!(
+        "{}\n\n=== CODEBASE REPORT ===\n\n{}",
+        DISCOVERY_REQUIREMENTS_PROMPT, codebase_report
+    );
+
+    // Step 3: Create messages for the LLM
+    let messages = vec![
+        Message::new(MessageRole::System, DISCOVERY_SYSTEM_PROMPT.to_string()),
+        Message::new(MessageRole::User, user_prompt),
+    ];
+
+    // Step 4: Send to LLM
+    let request = CompletionRequest {
+        messages,
+        max_tokens: Some(provider.max_tokens()),
+        temperature: Some(provider.temperature()),
+        stream: false,
+        tools: None,
+    };
+
+    status("🤖 Calling LLM for discovery commands...");
+
+    let response = provider.complete(request).await?;
+
+    // Step 5: Extract shell commands from the response
+    let shell_commands = extract_shell_commands(&response.content);
+
+    status(&format!("📋 Extracted {} discovery commands", shell_commands.len()));
+
+    // Step 6: Format as tool messages
+    let tool_messages = shell_commands
+        .into_iter()
+        .map(|cmd| create_tool_message("shell", &cmd))
+        .collect();
+
+    Ok(tool_messages)
+}
+
+/// Creates an Assistant message with a tool call in g3's JSON format.
+pub fn create_tool_message(tool: &str, command: &str) -> Message {
+    let tool_call = serde_json::json!({
+        "tool": tool,
+        "args": {
+            "command": command
+        }
+    });
+
+    Message::new(MessageRole::Assistant, tool_call.to_string())
+}
+
+/// Extract shell commands from the LLM response.
+/// Looks for {{CODE EXPLORATION COMMANDS}} section and extracts commands from code blocks.
+pub fn extract_shell_commands(response: &str) -> Vec<String> {
+    let mut commands = Vec::new();
+
+    let section_marker = "{{CODE EXPLORATION COMMANDS}}";
+    let section_start = match response.find(section_marker) {
+        Some(pos) => pos + section_marker.len(),
+        None => return commands,
+    };
+
+    let section_content = &response[section_start..];
+    let mut in_code_block = false;
+    let mut current_block = String::new();
+
+    for line in section_content.lines() {
+        let trimmed = line.trim();
+
+        if trimmed.starts_with("```") {
+            if in_code_block {
+                // End of code block - extract commands
+                for cmd_line in current_block.lines() {
+                    let cmd = cmd_line.trim();
+                    if !cmd.is_empty() && !cmd.starts_with('#') {
+                        commands.push(cmd.to_string());
+                    }
+                }
+                current_block.clear();
+            }
+            in_code_block = !in_code_block;
+        } else if in_code_block {
+            current_block.push_str(line);
+            current_block.push('\n');
+        }
+    }
+
+    commands
+}
+
+/// Extract the summary section from the LLM response
+pub fn extract_summary(response: &str) -> Option<String> {
+    let section_marker = "{{SUMMARY BASED ON INITIAL INFO}}";
+    let section_start = match response.find(section_marker) {
+        Some(pos) => pos + section_marker.len(),
+        None => return None,
+    };
+
+    let section_content = &response[section_start..];
+    let section_end = section_content.find("{{").unwrap_or(section_content.len());
+
+    let summary = section_content[..section_end].trim().to_string();
+    if summary.is_empty() {
+        None
+    } else {
+        Some(summary)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_create_tool_message_format() {
+        let msg = create_tool_message("shell", "ls -la");
+
+        assert!(matches!(msg.role, MessageRole::Assistant));
+
+        let parsed: serde_json::Value = serde_json::from_str(&msg.content).unwrap();
+        assert_eq!(parsed["tool"], "shell");
+        assert_eq!(parsed["args"]["command"], "ls -la");
+    }
+
+    #[test]
+    fn test_extract_shell_commands_basic() {
+        let response = r#"
+Some text here.
+
+{{CODE EXPLORATION COMMANDS}}
+
+```bash
+ls -la
+cat README.md
+rg --files -g '*.rs'
+```
+
+More text.
+"#;
+
+        let commands = extract_shell_commands(response);
+        assert_eq!(commands.len(), 3);
+        assert_eq!(commands[0], "ls -la");
+        assert_eq!(commands[1], "cat README.md");
+        assert_eq!(commands[2], "rg --files -g '*.rs'");
+    }
+
+    #[test]
+    fn test_extract_shell_commands_with_comments() {
+        let response = r#"
+{{CODE EXPLORATION COMMANDS}}
+
+```
+# This is a comment
+ls -la
+# Another comment
+cat file.txt
+```
+"#;
+
+        let commands = extract_shell_commands(response);
+        assert_eq!(commands.len(), 2);
+        assert_eq!(commands[0], "ls -la");
+        assert_eq!(commands[1], "cat file.txt");
+    }
+
+    #[test]
+    fn test_extract_shell_commands_no_section() {
+        let response = "Some response without the expected section.";
+        let commands = extract_shell_commands(response);
+        assert!(commands.is_empty());
+    }
+
+    #[test]
+    fn test_extract_summary() {
+        let response = r#"
+{{SUMMARY BASED ON INITIAL INFO}}
+
+This is a summary of the codebase.
+It has multiple lines.
+
+{{CODE EXPLORATION COMMANDS}}
+
+```
+ls -la
+```
+"#;
+
+        let summary = extract_summary(response);
+        assert!(summary.is_some());
+        let summary_text = summary.unwrap();
+        assert!(summary_text.contains("This is a summary"));
+        assert!(summary_text.contains("multiple lines"));
+    }
+
+    #[test]
+    fn test_extract_summary_no_section() {
+        let response = "Response without summary section.";
+        let summary = extract_summary(response);
+        assert!(summary.is_none());
+    }
+}

crates/g3-planner/src/prompts.rs

@@ -0,0 +1,31 @@
+//! Prompts used for discovery phase
+
+/// System prompt for discovery mode - instructs the LLM to analyze codebase and generate exploration commands
+pub const DISCOVERY_SYSTEM_PROMPT: &str = r#"You are an expert code analyst. Your task is to analyze a codebase structure and generate shell commands to explore it further.
+
+You will receive:
+1. User requirements describing what needs to be implemented
+2. A codebase report showing the structure and key elements of the codebase
+
+Your job is to:
+1. Understand the requirements and identify what parts of the codebase are relevant
+2. Generate shell commands to explore those parts in more detail
+
+IMPORTANT: Do NOT attempt to implement anything. Only generate exploration commands."#;
+
+/// Discovery prompt template - used when we have a codebase report.
+/// The codebase report should be appended after this prompt.
+pub const DISCOVERY_REQUIREMENTS_PROMPT: &str = r#"**CRITICAL**: DO ABSOLUTELY NOT ATTEMPT TO IMPLEMENT THESE REQUIREMENTS AT THIS POINT. ONLY USE THEM TO
+UNDERSTAND WHICH PARTS OF THE CODE YOU MIGHT BE INTERESTED IN, AND WHAT SEARCH/GREP EXPRESSIONS YOU MIGHT WANT TO USE
+TO GET A BETTER UNDERSTANDING OF THE CODEBASE.
+
+Your task is to analyze the codebase structure provided below and generate shell commands to explore it further.
+
+Your output MUST include:
+1. A section with heading {{SUMMARY BASED ON INITIAL INFO}} containing a brief summary of what you understand about the codebase structure (max 10000 tokens).
+2. A section with heading {{CODE EXPLORATION COMMANDS}} containing shell commands to explore the codebase further.
+   - Use tools like `ls`, `rg` (ripgrep), `grep`, `sed`, `cat`, `head`, `tail` etc.
+   - Focus on commands that will help understand the code structure without dumping entire files.
+   - Mark the beginning and end of the commands with "```".
+
+DO NOT ADD ANY COMMENTS OR OTHER EXPLANATION IN THE COMMANDS SECTION, JUST INCLUDE THE SHELL COMMANDS."#;

crates/g3-planner/tests/planner_test.rs

@@ -0,0 +1,103 @@
+//! Integration tests for g3-planner
+
+use g3_planner::{create_tool_message, explore_codebase, extract_shell_commands};
+use g3_providers::MessageRole;
+
+#[test]
+fn test_create_tool_message_format() {
+    let msg = create_tool_message("shell", "ls -la");
+
+    assert!(matches!(msg.role, MessageRole::Assistant));
+
+    let parsed: serde_json::Value = serde_json::from_str(&msg.content).unwrap();
+    assert_eq!(parsed["tool"], "shell");
+    assert_eq!(parsed["args"]["command"], "ls -la");
+}
+
+#[test]
+fn test_explore_codebase_returns_report() {
+    // Test with current directory (should find Rust files in g3 project)
+    let report = explore_codebase(".");
+
+    // Should return a non-empty report
+    assert!(!report.is_empty(), "Report should not be empty");
+
+    // Should contain the codebase analysis header
+    assert!(
+        report.contains("CODEBASE ANALYSIS") || report.contains("No recognized"),
+        "Report should have analysis header or indicate no languages found"
+    );
+}
+
+#[test]
+fn test_extract_shell_commands_basic() {
+    let response = r#"
+Some text here.
+
+{{CODE EXPLORATION COMMANDS}}
+
+```bash
+ls -la
+cat README.md
+rg --files -g '*.rs'
+```
+
+More text.
+"#;
+
+    let commands = extract_shell_commands(response);
+    assert_eq!(commands.len(), 3);
+    assert_eq!(commands[0], "ls -la");
+    assert_eq!(commands[1], "cat README.md");
+    assert_eq!(commands[2], "rg --files -g '*.rs'");
+}
+
+#[test]
+fn test_extract_shell_commands_with_comments() {
+    let response = r#"
+{{CODE EXPLORATION COMMANDS}}
+
+```
+# This is a comment
+ls -la
+# Another comment
+cat file.txt
+```
+"#;
+
+    let commands = extract_shell_commands(response);
+    assert_eq!(commands.len(), 2);
+    assert_eq!(commands[0], "ls -la");
+    assert_eq!(commands[1], "cat file.txt");
+}
+
+#[test]
+fn test_extract_shell_commands_no_section() {
+    let response = "Some response without the expected section.";
+    let commands = extract_shell_commands(response);
+    assert!(commands.is_empty());
+}
+
+#[test]
+fn test_extract_shell_commands_multiple_code_blocks() {
+    let response = r#"
+{{CODE EXPLORATION COMMANDS}}
+
+```bash
+ls -la
+```
+
+Some explanation text.
+
+```
+cat README.md
+head -50 src/main.rs
+```
+"#;
+
+    let commands = extract_shell_commands(response);
+    assert_eq!(commands.len(), 3);
+    assert_eq!(commands[0], "ls -la");
+    assert_eq!(commands[1], "cat README.md");
+    assert_eq!(commands[2], "head -50 src/main.rs");
+}

crates/g3-providers/src/anthropic.rs

@@ -678,6 +678,14 @@ impl LLMProvider for AnthropicProvider {
         // Anthropic supports cache control
         true
     }
+    
+    fn max_tokens(&self) -> u32 {
+        self.max_tokens
+    }
+    
+    fn temperature(&self) -> f32 {
+        self.temperature
+    }
 }
 
 // Anthropic API request/response structures

crates/g3-providers/src/databricks.rs

@@ -1055,6 +1055,14 @@ impl LLMProvider for DatabricksProvider {
     fn supports_cache_control(&self) -> bool {
         false
     }
+    
+    fn max_tokens(&self) -> u32 {
+        self.max_tokens
+    }
+    
+    fn temperature(&self) -> f32 {
+        self.temperature
+    }
 }
 
 // Databricks API request/response structures

crates/g3-providers/src/embedded.rs

@@ -771,4 +771,12 @@ impl LLMProvider for EmbeddedProvider {
     fn model(&self) -> &str {
         &self.model_name
     }
+    
+    fn max_tokens(&self) -> u32 {
+        self.max_tokens
+    }
+    
+    fn temperature(&self) -> f32 {
+        self.temperature
+    }
 }

crates/g3-providers/src/lib.rs

@@ -26,6 +26,12 @@ pub trait LLMProvider: Send + Sync {
     fn supports_cache_control(&self) -> bool {
         false
     }
+    
+    /// Get the configured max_tokens for this provider
+    fn max_tokens(&self) -> u32;
+    
+    /// Get the configured temperature for this provider
+    fn temperature(&self) -> f32;
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]

crates/g3-providers/src/openai.rs

@@ -384,6 +384,14 @@ impl LLMProvider for OpenAIProvider {
         // OpenAI models support native tool calling
         true
     }
+    
+    fn max_tokens(&self) -> u32 {
+        self.max_tokens.unwrap_or(16000)
+    }
+    
+    fn temperature(&self) -> f32 {
+        self._temperature.unwrap_or(0.1)
+    }
 }
 
 fn convert_messages(messages: &[Message]) -> Vec<serde_json::Value> {