Add extensible tool system with code execution and web search

Introduces a tool registry architecture with sandboxed code execution, web search capabilities, and consent-based permission management. Enables safe, pluggable LLM tool integration with schema validation.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

crates/owlen-core/src/tools/code_exec.rs

@@ -0,0 +1,147 @@
+use std::sync::Arc;
+use std::time::Instant;
+
+use anyhow::{anyhow, Context, Result};
+use async_trait::async_trait;
+use serde_json::{json, Value};
+
+use super::{Tool, ToolResult};
+use crate::sandbox::{SandboxConfig, SandboxedProcess};
+
+pub struct CodeExecTool {
+    allowed_languages: Arc<Vec<String>>,
+}
+
+impl CodeExecTool {
+    pub fn new(allowed_languages: Vec<String>) -> Self {
+        Self {
+            allowed_languages: Arc::new(allowed_languages),
+        }
+    }
+}
+
+#[async_trait]
+impl Tool for CodeExecTool {
+    fn name(&self) -> &'static str {
+        "code_exec"
+    }
+
+    fn description(&self) -> &'static str {
+        "Execute code snippets within a sandboxed environment"
+    }
+
+    fn schema(&self) -> Value {
+        json!({
+            "type": "object",
+            "properties": {
+                "language": {
+                    "type": "string",
+                    "enum": self.allowed_languages.as_slice(),
+                    "description": "Language of the code block"
+                },
+                "code": {
+                    "type": "string",
+                    "minLength": 1,
+                    "maxLength": 10000,
+                    "description": "Code to execute"
+                },
+                "timeout": {
+                    "type": "integer",
+                    "minimum": 1,
+                    "maximum": 300,
+                    "default": 30,
+                    "description": "Execution timeout in seconds"
+                }
+            },
+            "required": ["language", "code"],
+            "additionalProperties": false
+        })
+    }
+
+    async fn execute(&self, args: Value) -> Result<ToolResult> {
+        let start = Instant::now();
+
+        let language = args
+            .get("language")
+            .and_then(Value::as_str)
+            .context("Missing language parameter")?;
+        let code = args
+            .get("code")
+            .and_then(Value::as_str)
+            .context("Missing code parameter")?;
+        let timeout = args.get("timeout").and_then(Value::as_u64).unwrap_or(30);
+
+        if !self.allowed_languages.iter().any(|lang| lang == language) {
+            return Err(anyhow!("Language '{}' not permitted", language));
+        }
+
+        let (command, command_args) = match language {
+            "python" => (
+                "python3".to_string(),
+                vec!["-c".to_string(), code.to_string()],
+            ),
+            "javascript" => ("node".to_string(), vec!["-e".to_string(), code.to_string()]),
+            "bash" => ("bash".to_string(), vec!["-c".to_string(), code.to_string()]),
+            "rust" => {
+                let mut result =
+                    ToolResult::error("Rust execution is not yet supported in the sandbox");
+                result.duration = start.elapsed();
+                return Ok(result);
+            }
+            other => return Err(anyhow!("Unsupported language: {}", other)),
+        };
+
+        let sandbox_config = SandboxConfig {
+            allow_network: false,
+            timeout_seconds: timeout,
+            ..Default::default()
+        };
+
+        let sandbox_result = tokio::task::spawn_blocking(move || -> Result<_> {
+            let sandbox = SandboxedProcess::new(sandbox_config)?;
+            let arg_refs: Vec<&str> = command_args.iter().map(|s| s.as_str()).collect();
+            sandbox.execute(&command, &arg_refs)
+        })
+        .await
+        .context("Sandbox execution task failed")??;
+
+        let mut result = if sandbox_result.exit_code == 0 {
+            ToolResult::success(json!({
+                "stdout": sandbox_result.stdout,
+                "stderr": sandbox_result.stderr,
+                "exit_code": sandbox_result.exit_code,
+                "timed_out": sandbox_result.was_timeout,
+            }))
+        } else {
+            let error_msg = if sandbox_result.was_timeout {
+                format!(
+                    "Execution timed out after {} seconds (exit code {}): {}",
+                    timeout, sandbox_result.exit_code, sandbox_result.stderr
+                )
+            } else {
+                format!(
+                    "Execution failed with status {}: {}",
+                    sandbox_result.exit_code, sandbox_result.stderr
+                )
+            };
+            let mut err_result = ToolResult::error(&error_msg);
+            err_result.output = json!({
+                "stdout": sandbox_result.stdout,
+                "stderr": sandbox_result.stderr,
+                "exit_code": sandbox_result.exit_code,
+                "timed_out": sandbox_result.was_timeout,
+            });
+            err_result
+        };
+
+        result.duration = start.elapsed();
+        result
+            .metadata
+            .insert("language".to_string(), language.to_string());
+        result
+            .metadata
+            .insert("timeout_seconds".to_string(), timeout.to_string());
+
+        Ok(result)
+    }
+}