Add [execution] section to TOML task config for execution environment

Allow specifying execution environment (local/docker/daytona) in TOML
task configs so pipelines are self-contained. CLI flag takes precedence
over TOML, which takes precedence over the default (local).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Entire-Checkpoint: 600b7720bbda

crates/attractor/src/cli/mod.rs

@@ -105,8 +105,8 @@ pub struct RunArgs {
     pub verbose: u8,
 
     /// Execution environment for agent tools
-    #[arg(long, value_enum, default_value_t)]
-    pub execution_env: ExecutionEnvKind,
+    #[arg(long, value_enum)]
+    pub execution_env: Option<ExecutionEnvKind>,
 }
 
 #[derive(Args)]
@@ -139,8 +139,8 @@ pub struct ServeArgs {
     pub dry_run: bool,
 
     /// Execution environment for agent tools
-    #[arg(long, value_enum, default_value_t)]
-    pub execution_env: ExecutionEnvKind,
+    #[arg(long, value_enum)]
+    pub execution_env: Option<ExecutionEnvKind>,
 }
 
 /// Read a .dot file from disk.

crates/attractor/src/cli/run.rs

@@ -18,7 +18,7 @@ use crate::validation::Severity;
 
 use super::backend::AgentBackend;
 use super::task_config;
-use super::{compute_stage_cost, format_cost, format_duration_human, format_event_detail, format_event_summary, format_tokens_human, print_diagnostics, read_dot_file, RunArgs};
+use super::{compute_stage_cost, format_cost, format_duration_human, format_event_detail, format_event_summary, format_tokens_human, print_diagnostics, read_dot_file, ExecutionEnvKind, RunArgs};
 
 /// Accumulates token usage and cost across all pipeline stages.
 #[derive(Default)]
@@ -218,7 +218,17 @@ pub async fn run_command(args: RunArgs, styles: &'static Styles) -> anyhow::Resu
         Arc::new(ConsoleInterviewer::new(styles))
     };
 
-    // 5. Resolve backend, model, and provider
+    // 5. Resolve execution environment: CLI flag > TOML > default
+    let toml_execution_env = task_cfg
+        .as_ref()
+        .and_then(|c| c.execution.as_ref())
+        .and_then(|e| e.environment.as_deref())
+        .map(|s| s.parse::<ExecutionEnvKind>())
+        .transpose()
+        .map_err(|e| anyhow::anyhow!("Invalid execution environment in TOML: {e}"))?;
+    let execution_env = args.execution_env.or(toml_execution_env).unwrap_or_default();
+
+    // 6. Resolve backend, model, and provider
     let dry_run_mode = if args.dry_run {
         true
     } else {
@@ -294,7 +304,7 @@ pub async fn run_command(args: RunArgs, styles: &'static Styles) -> anyhow::Resu
                 provider.clone(),
                 args.verbose,
                 styles,
-                args.execution_env,
+                execution_env,
                 setup_commands.clone(),
             )))
         }

crates/attractor/src/cli/serve.rs

@@ -66,7 +66,7 @@ pub async fn serve_command(args: ServeArgs, styles: &'static Styles) -> anyhow::
                     provider.clone(),
                     0,
                     styles,
-                    args.execution_env,
+                    args.execution_env.unwrap_or_default(),
                     Vec::new(),
                 )))
             }

crates/attractor/src/cli/task_config.rs

@@ -14,6 +14,7 @@ pub struct TaskConfig {
     pub directory: Option<String>,
     pub llm: Option<LlmConfig>,
     pub setup: Option<SetupConfig>,
+    pub execution: Option<ExecutionConfig>,
     pub vars: Option<HashMap<String, String>>,
 }
 
@@ -29,6 +30,11 @@ pub struct SetupConfig {
     pub timeout_ms: Option<u64>,
 }
 
+#[derive(Debug, Deserialize)]
+pub struct ExecutionConfig {
+    pub environment: Option<String>,
+}
+
 /// Load and validate a task config from a TOML file.
 ///
 /// The `graph` path in the returned config is resolved relative to the
@@ -201,6 +207,21 @@ language = "python"
         assert_eq!(expand_vars("costs $5", &vars).unwrap(), "costs $5");
     }
 
+    #[test]
+    fn parse_toml_with_execution() {
+        let toml = r#"
+version = 1
+task = "Run tests"
+graph = "pipeline.dot"
+
+[execution]
+environment = "daytona"
+"#;
+        let config = parse_task_config(toml).unwrap();
+        let execution = config.execution.unwrap();
+        assert_eq!(execution.environment.as_deref(), Some("daytona"));
+    }
+
     #[test]
     fn parse_minimal_toml() {
         let toml = r#"