feat: load global prompts at startup, add minijinja crate (#1467)

crates/goose/Cargo.toml

@@ -37,7 +37,7 @@ uuid = { version = "1.0", features = ["v4"] }
 regex = "1.11.1"
 async-trait = "0.1"
 async-stream = "0.3"
-tera = "1.20.0"
+minijinja = "2.8.0"
 tokenizers = "0.20.3"
 include_dir = "0.7.4"
 chrono = { version = "0.4.38", features = ["serde"] }

crates/goose/src/agents/capabilities.rs

@@ -11,7 +11,7 @@ use tokio::sync::Mutex;
 use tracing::{debug, instrument};
 
 use super::extension::{ExtensionConfig, ExtensionError, ExtensionInfo, ExtensionResult};
-use crate::prompt_template::{load_prompt, load_prompt_file};
+use crate::prompt_template;
 use crate::providers::base::{Provider, ProviderUsage};
 use mcp_client::client::{ClientCapabilities, ClientInfo, McpClient, McpClientTrait};
 use mcp_client::transport::{SseTransport, StdioTransport, Transport};
@@ -340,12 +340,13 @@ impl Capabilities {
         context.insert("extensions", serde_json::to_value(extensions_info).unwrap());
         context.insert("current_date_time", Value::String(current_date_time));
 
-        // Conditionally load the override prompt or the default system prompt
-        // and set the base prompt to the context
+        // Conditionally load the override prompt or the global system prompt
         let base_prompt = if let Some(override_prompt) = &self.system_prompt_override {
-            load_prompt(override_prompt, &context).expect("Prompt should render")
+            prompt_template::render_inline_once(override_prompt, &context)
+                .expect("Prompt should render")
         } else {
-            load_prompt_file("system.md", &context).expect("Prompt should render")
+            prompt_template::render_global_file("system.md", &context)
+                .expect("Prompt should render")
         };
 
         if self.system_prompt_extensions.is_empty() {

crates/goose/src/prompt_template.rs

@@ -1,78 +1,162 @@
 use include_dir::{include_dir, Dir};
+use minijinja::{Environment, Error as MiniJinjaError, Value as MJValue};
+use once_cell::sync::Lazy;
 use serde::Serialize;
 use std::path::PathBuf;
-use tera::{Context, Error as TeraError, Tera};
+use std::sync::{Arc, RwLock};
 
-// The prompts directory needs to be embedded in the binary (so it works when distributed)
-static PROMPTS_DIR: Dir = include_dir!("$CARGO_MANIFEST_DIR/src/prompts");
+/// This directory will be embedded into the final binary.
+/// Typically used to store "core" or "system" prompts.
+static CORE_PROMPTS_DIR: Dir = include_dir!("$CARGO_MANIFEST_DIR/src/prompts");
 
-pub fn load_prompt<T: Serialize>(template: &str, context_data: &T) -> Result<String, TeraError> {
-    let mut tera = Tera::default();
-    tera.add_raw_template("inline_template", template)?;
-    let context = Context::from_serialize(context_data)?;
-    let rendered = tera.render("inline_template", &context)?;
+/// A global MiniJinja environment storing the "core" prompts.
+///
+/// - Loaded at startup from the `CORE_PROMPTS_DIR`.
+/// - Ideal for "system" templates that don't change often.
+/// - *Not* used for extension prompts (which are ephemeral).
+static GLOBAL_ENV: Lazy<Arc<RwLock<Environment<'static>>>> = Lazy::new(|| {
+    let mut env = Environment::new();
+
+    // Pre-load all core templates from the embedded dir.
+    for file in CORE_PROMPTS_DIR.files() {
+        let name = file.path().to_string_lossy().to_string();
+        let source = String::from_utf8_lossy(file.contents()).to_string();
+
+        // Since we're using 'static lifetime for the Environment, we need to ensure
+        // the strings we add as templates live for the entire program duration.
+        // We can achieve this by leaking the strings (acceptable for initialization).
+        let static_name: &'static str = Box::leak(name.into_boxed_str());
+        let static_source: &'static str = Box::leak(source.into_boxed_str());
+
+        if let Err(e) = env.add_template(static_name, static_source) {
+            tracing::error!("Failed to add template {}: {}", static_name, e);
+        }
+    }
+
+    Arc::new(RwLock::new(env))
+});
+
+/// Renders a prompt from the global environment by name.
+///
+/// # Arguments
+/// * `template_name` - The name of the template (usually the file path or a custom ID).
+/// * `context_data`  - Data to be inserted into the template (must be `Serialize`).
+pub fn render_global_template<T: Serialize>(
+    template_name: &str,
+    context_data: &T,
+) -> Result<String, MiniJinjaError> {
+    let env = GLOBAL_ENV.read().expect("GLOBAL_ENV lock poisoned");
+    let tmpl = env.get_template(template_name)?;
+    let ctx = MJValue::from_serialize(context_data);
+    let rendered = tmpl.render(ctx)?;
     Ok(rendered.trim().to_string())
 }
 
-pub fn load_prompt_file<T: Serialize>(
+/// Renders a file from `CORE_PROMPTS_DIR` within the global environment.
+///
+/// # Arguments
+/// * `template_file` - The file path within the embedded directory (e.g. "system.md").
+/// * `context_data`  - Data to be inserted into the template (must be `Serialize`).
+///
+/// This function **assumes** the file is already in `CORE_PROMPTS_DIR`. If it wasn't
+/// added to the global environment at startup (due to parse errors, etc.), this will error out.
+pub fn render_global_file<T: Serialize>(
     template_file: impl Into<PathBuf>,
     context_data: &T,
-) -> Result<String, TeraError> {
-    let template_path = template_file.into();
+) -> Result<String, MiniJinjaError> {
+    let file_path = template_file.into();
+    let template_name = file_path.to_string_lossy().to_string();
 
-    // Get the file content from the embedded directory
-    let template_content = if let Some(file) = PROMPTS_DIR.get_file(template_path.to_str().unwrap())
-    {
-        String::from_utf8_lossy(file.contents()).into_owned()
-    } else {
-        return Err(TeraError::chain(
-            "Failed to find template file",
-            std::io::Error::new(
-                std::io::ErrorKind::NotFound,
-                "Template file not found in embedded directory",
-            ),
-        ));
-    };
+    render_global_template(&template_name, context_data)
+}
 
-    load_prompt(&template_content, context_data)
+/// Alias for render_global_file for backward compatibility
+pub fn render_global_from_file<T: Serialize>(
+    template_file: impl Into<PathBuf>,
+    context_data: &T,
+) -> Result<String, MiniJinjaError> {
+    render_global_file(template_file, context_data)
+}
+
+/// Renders a **one-off ephemeral** template (inline string).
+///
+/// This does *not* store anything in the global environment and is best for
+/// extension prompts or user-supplied templates that are used infrequently.
+///
+/// # Arguments
+/// * `template_str`  - The raw template string.
+/// * `context_data`  - Data to be inserted into the template (must be `Serialize`).
+pub fn render_inline_once<T: Serialize>(
+    template_str: &str,
+    context_data: &T,
+) -> Result<String, MiniJinjaError> {
+    let mut env = Environment::new();
+    env.add_template("inline_ephemeral", template_str)?;
+    let tmpl = env.get_template("inline_ephemeral")?;
+    let ctx = MJValue::from_serialize(context_data);
+    let rendered = tmpl.render(ctx)?;
+    Ok(rendered.trim().to_string())
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
-    use mcp_core::tool::Tool;
     use serde_json::json;
     use std::collections::HashMap;
 
-    #[test]
-    fn test_load_prompt() {
-        let template = "Hello, {{ name }}! You are {{ age }} years old.";
-        let mut context = HashMap::new();
-        context.insert("name".to_string(), "Alice".to_string());
-        context.insert("age".to_string(), 30.to_string());
+    /// For convenience in tests, define a small struct or use a HashMap to provide context.
+    #[derive(Serialize)]
+    struct TestContext {
+        name: String,
+        age: u32,
+    }
 
-        let result = load_prompt(template, &context).unwrap();
+    // A simple function to help us test missing or partial data
+    fn build_context(name: Option<&str>, age: Option<u32>) -> HashMap<String, serde_json::Value> {
+        let mut ctx = HashMap::new();
+        if let Some(n) = name {
+            ctx.insert("name".to_string(), json!(n));
+        }
+        if let Some(a) = age {
+            ctx.insert("age".to_string(), json!(a));
+        }
+        ctx
+    }
+
+    #[test]
+    fn test_render_inline_once_basic() {
+        let template_str = "Hello, {{ name }}! You are {{ age }} years old.";
+        let context = TestContext {
+            name: "Alice".to_string(),
+            age: 30,
+        };
+
+        let result = render_inline_once(template_str, &context).unwrap();
         assert_eq!(result, "Hello, Alice! You are 30 years old.");
     }
 
     #[test]
-    fn test_load_prompt_missing_variable() {
-        let template = "Hello, {{ name }}! You are {{ age }} years old.";
-        let mut context = HashMap::new();
-        context.insert("name".to_string(), "Alice".to_string());
-        // 'age' is missing from context
-        let result = load_prompt(template, &context);
-        assert!(result.is_err());
+    fn test_render_inline_missing_variable() {
+        let template_str = "Hello, {{ name }}! You are {{ age }} years old.";
+        let context = build_context(Some("Alice"), None);
+        // MiniJinja doesn't fail on missing variables, it renders them as empty strings
+        // So we should check that it renders successfully but with missing data
+        let result = render_inline_once(template_str, &context).unwrap();
+        assert!(result.contains("Hello, Alice! You are  years old."));
     }
 
     #[test]
-    fn test_load_prompt_file() {
-        // since we are embedding the prompts directory, the file path needs to be relative to the prompts directory
-        let file_path = PathBuf::from("mock.md");
-        let mut context = HashMap::new();
-        context.insert("name".to_string(), "Alice".to_string());
-        context.insert("age".to_string(), 30.to_string());
-        let result = load_prompt_file(file_path, &context).unwrap();
+    fn test_global_file_render() {
+        // "mock.md" should exist in the embedded CORE_PROMPTS_DIR
+        // and have placeholders for `name` and `age`.
+        let context = TestContext {
+            name: "Alice".to_string(),
+            age: 30,
+        };
+
+        let result = render_global_file("mock.md", &context).unwrap();
+        // Assume mock.md content is something like:
+        //  "This prompt is only used for testing.\n\nHello, {{ name }}! You are {{ age }} years old."
         assert_eq!(
             result,
             "This prompt is only used for testing.\n\nHello, Alice! You are 30 years old."
@@ -80,60 +164,75 @@ mod tests {
     }
 
     #[test]
-    fn test_load_prompt_file_missing_file() {
-        let file_path = PathBuf::from("non_existent_template.txt");
-        let context: HashMap<String, String> = HashMap::new(); // Add type annotation here
+    fn test_global_file_not_found() {
+        let context = TestContext {
+            name: "Unused".to_string(),
+            age: 99,
+        };
 
-        let result = load_prompt_file(file_path, &context);
-        assert!(result.is_err());
+        let result = render_global_file("non_existent.md", &context);
+        assert!(result.is_err(), "Should fail because file is missing");
     }
 
     #[test]
-    fn test_load_prompt_with_tools() {
-        let template = "### Tool Descriptions\n{% for tool in tools %}\n{{tool.name}}: {{tool.description}}{% endfor %}";
+    fn test_inline_complex_object() {
+        // Example with more complex data.
+        #[derive(Serialize)]
+        struct Tool {
+            name: String,
+            description: String,
+        }
 
-        let tools = vec![
-            Tool::new(
-                "calculator",
-                "Performs basic math operations",
-                json!({
-                    "type": "object",
-                    "properties": {
-                        "operation": {"type": "string"},
-                        "numbers": {"type": "array"}
-                    }
-                }),
-            ),
-            Tool::new(
-                "weather",
-                "Gets weather information",
-                json!({
-                    "type": "object",
-                    "properties": {
-                        "location": {"type": "string"}
-                    }
-                }),
-            ),
-        ];
+        #[derive(Serialize)]
+        struct ToolsContext {
+            tools: Vec<Tool>,
+        }
 
-        let mut context = HashMap::new();
-        context.insert("tools".to_string(), tools);
+        let template_str = "\
+### Tool Descriptions
+{% for tool in tools %}
+- {{ tool.name }}: {{ tool.description }}
+{% endfor %}";
 
-        let result = load_prompt(template, &context).unwrap();
-        let expected = "### Tool Descriptions\n\ncalculator: Performs basic math operations\nweather: Gets weather information";
-        assert_eq!(result, expected);
+        let context = ToolsContext {
+            tools: vec![
+                Tool {
+                    name: "calculator".to_string(),
+                    description: "Performs basic math operations".to_string(),
+                },
+                Tool {
+                    name: "weather".to_string(),
+                    description: "Gets weather information".to_string(),
+                },
+            ],
+        };
+
+        let rendered = render_inline_once(template_str, &context).unwrap();
+        let expected = "\
+### Tool Descriptions
+
+- calculator: Performs basic math operations
+
+- weather: Gets weather information";
+        assert_eq!(rendered, expected);
     }
 
     #[test]
-    fn test_load_prompt_with_empty_tools() {
-        let template = "### Tool Descriptions\n{% for tool in tools %}\n{{tool.name}}: {{tool.description}}{% endfor %}";
+    fn test_inline_with_empty_list() {
+        let template_str = "\
+### Tool Descriptions
+{% for tool in tools %}
+- {{ tool.name }}: {{ tool.description }}
+{% endfor %}";
 
-        let tools: Vec<Tool> = vec![];
-        let mut context = HashMap::new();
-        context.insert("tools".to_string(), tools);
+        #[derive(Serialize)]
+        struct ToolsContext {
+            tools: Vec<String>, // or a struct if needed
+        }
 
-        let result = load_prompt(template, &context).unwrap();
+        let context = ToolsContext { tools: vec![] };
+        let rendered = render_inline_once(template_str, &context).unwrap();
         let expected = "### Tool Descriptions";
-        assert_eq!(result, expected);
+        assert_eq!(rendered, expected);
     }
 }