diff --git a/crates/mcp/src/lib.rs b/crates/mcp/src/lib.rs
index c3fd10f5..df2325cd 100644
--- a/crates/mcp/src/lib.rs
+++ b/crates/mcp/src/lib.rs
@@ -318,8 +318,31 @@ impl McpManager {
         qualified_tool_name: &str,
         arguments: Value,
     ) -> Result<Value> {
-        let (server_name, tool_name) = parse_qualified_tool_name(qualified_tool_name)
-            .with_context(|| format!("invalid qualified MCP tool name: {qualified_tool_name}"))?;
+        let parsed = parse_qualified_tool_name(qualified_tool_name)
+            .with_context(|| format!("invalid qualified MCP tool name: {qualified_tool_name}"));
+
+        if let Ok((server_name, tool_name)) = &parsed
+            && self.clients.contains_key(server_name)
+            && let Ok(result) = self.call_tool(server_name, tool_name, arguments.clone())
+        {
+            return Ok(result);
+        }
+
+        for (server_name, (_, filter)) in &self.configs {
+            let Some(client) = self.clients.get(server_name) else {
+                continue;
+            };
+            for tool in client.list_tools()? {
+                if !allowed_by_filter(&tool.tool_name, filter) {
+                    continue;
+                }
+                if qualify_tool_name(server_name, &tool.tool_name) == qualified_tool_name {
+                    return client.call_tool(&tool.tool_name, arguments);
+                }
+            }
+        }
+
+        let (server_name, tool_name) = parsed?;
         self.call_tool(&server_name, &tool_name, arguments)
     }
 
@@ -392,18 +415,29 @@ fn sanitize_component(value: &str) -> String {
 }
 
 fn qualify_tool_name(server: &str, tool: &str) -> String {
-    let mut name = format!(
-        "mcp__{}__{}",
-        sanitize_component(server),
-        sanitize_component(tool)
-    );
+    let server = sanitize_component(server);
+    let tool = sanitize_component(tool);
+    let mut name = format!("mcp__{server}__{tool}");
     if name.len() > 64 {
         let mut hasher = DefaultHasher::new();
         name.hash(&mut hasher);
         let hash = format!("{:x}", hasher.finish());
-        name.truncate(48);
-        name.push('_');
-        name.push_str(&hash[..12]);
+        let suffix = format!("_{}", &hash[..12]);
+        let component_budget = 64 - "mcp__".len() - "__".len() - suffix.len();
+        let mut server_len = server.len().min(component_budget / 2);
+        let mut tool_len = tool.len().min(component_budget - server_len);
+        let remaining = component_budget - server_len - tool_len;
+        if remaining > 0 {
+            let server_extra = (server.len() - server_len).min(remaining);
+            server_len += server_extra;
+            tool_len += (tool.len() - tool_len).min(remaining - server_extra);
+        }
+        name = format!(
+            "mcp__{}__{}{}",
+            &server[..server_len],
+            &tool[..tool_len],
+            suffix
+        );
     }
     name
 }
@@ -957,3 +991,416 @@ impl JsonRpcError {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    // ── InMemoryMcpClient ──────────────────────────────────────────────
+
+    #[test]
+    fn in_memory_client_list_tools_returns_registered() {
+        let client = InMemoryMcpClient::default()
+            .with_tool("echo", json!({"output": "hi"}))
+            .with_tool("greet", json!({"msg": "hello"}));
+        let tools = client.list_tools().unwrap();
+        assert_eq!(tools.len(), 2);
+        let names: Vec<&str> = tools.iter().map(|t| t.tool_name.as_str()).collect();
+        assert!(names.contains(&"echo"));
+        assert!(names.contains(&"greet"));
+    }
+
+    #[test]
+    fn in_memory_client_call_tool_returns_value() {
+        let client = InMemoryMcpClient::default().with_tool("echo", json!({"output": "hi"}));
+        let result = client.call_tool("echo", json!({})).unwrap();
+        assert_eq!(result["output"], "hi");
+    }
+
+    #[test]
+    fn in_memory_client_call_tool_errors_on_missing() {
+        let client = InMemoryMcpClient::default();
+        let err = client.call_tool("nope", json!({})).unwrap_err();
+        assert!(err.to_string().contains("not found"));
+    }
+
+    #[test]
+    fn in_memory_client_list_resources_returns_registered() {
+        let client = InMemoryMcpClient::default()
+            .with_resource("mcp://s/health", json!({"ok": true}))
+            .with_resource("mcp://s/caps", json!({"tools": []}));
+        let resources = client.list_resources().unwrap();
+        assert_eq!(resources.len(), 2);
+    }
+
+    #[test]
+    fn in_memory_client_read_resource_returns_value() {
+        let client =
+            InMemoryMcpClient::default().with_resource("mcp://s/health", json!({"ok": true}));
+        let result = client.read_resource("mcp://s/health").unwrap();
+        assert_eq!(result["ok"], true);
+    }
+
+    #[test]
+    fn in_memory_client_read_resource_errors_on_missing() {
+        let client = InMemoryMcpClient::default();
+        let err = client.read_resource("mcp://s/nope").unwrap_err();
+        assert!(err.to_string().contains("not found"));
+    }
+
+    // ── McpManager ─────────────────────────────────────────────────────
+
+    fn make_server_config(name: &str) -> McpServerConfig {
+        McpServerConfig {
+            name: name.to_string(),
+            command: "test".to_string(),
+            args: vec![],
+            env: HashMap::new(),
+            enabled: true,
+        }
+    }
+
+    #[test]
+    fn manager_start_all_marks_ready_for_registered_clients() {
+        let mut manager = McpManager::default();
+        manager.register_server(
+            make_server_config("s1"),
+            ToolFilter::default(),
+            Box::new(InMemoryMcpClient::default().with_tool("t", json!(null))),
+        );
+        let mut events = Vec::new();
+        let summary = manager.start_all(|e| events.push(e));
+        assert_eq!(summary.ready, vec!["s1"]);
+        assert!(summary.failed.is_empty());
+        assert!(events.iter().any(|event| {
+            event.server_name == "s1" && event.status == McpStartupStatus::Starting
+        }));
+        assert!(
+            events.iter().any(|event| {
+                event.server_name == "s1" && event.status == McpStartupStatus::Ready
+            })
+        );
+    }
+
+    #[test]
+    fn manager_start_all_marks_failed_when_client_missing() {
+        let mut manager = McpManager::default();
+        manager.register_server(
+            make_server_config("s1"),
+            ToolFilter::default(),
+            Box::new(InMemoryMcpClient::default()),
+        );
+        manager.stop_server("s1").unwrap();
+        let summary = manager.start_all(|_| {});
+        assert!(summary.ready.is_empty());
+        assert_eq!(summary.failed.len(), 1);
+        assert_eq!(summary.failed[0].server_name, "s1");
+    }
+
+    #[test]
+    fn manager_start_all_cancels_disabled_servers() {
+        let mut manager = McpManager::default();
+        let mut cfg = make_server_config("s1");
+        cfg.enabled = false;
+        manager.register_server(
+            cfg,
+            ToolFilter::default(),
+            Box::new(InMemoryMcpClient::default()),
+        );
+        let summary = manager.start_all(|_| {});
+        assert!(summary.ready.is_empty());
+        assert_eq!(summary.cancelled, vec!["s1"]);
+    }
+
+    #[test]
+    fn manager_list_tools_applies_filter() {
+        let mut manager = McpManager::default();
+        let client = InMemoryMcpClient::default()
+            .with_tool("allowed", json!(null))
+            .with_tool("denied", json!(null));
+        manager.register_server(
+            make_server_config("s1"),
+            ToolFilter {
+                allow: vec!["allowed".to_string()],
+                deny: vec![],
+            },
+            Box::new(client),
+        );
+        let tools = manager.list_tools().unwrap();
+        assert_eq!(tools.len(), 1);
+        assert_eq!(tools[0].tool_name, "allowed");
+    }
+
+    #[test]
+    fn manager_list_tools_deny_overrides_allow() {
+        let mut manager = McpManager::default();
+        let client = InMemoryMcpClient::default()
+            .with_tool("a", json!(null))
+            .with_tool("b", json!(null));
+        manager.register_server(
+            make_server_config("s1"),
+            ToolFilter {
+                allow: vec!["a".to_string(), "b".to_string()],
+                deny: vec!["b".to_string()],
+            },
+            Box::new(client),
+        );
+        let tools = manager.list_tools().unwrap();
+        assert_eq!(tools.len(), 1);
+        assert_eq!(tools[0].tool_name, "a");
+    }
+
+    #[test]
+    fn manager_call_tool_delegates_to_client() {
+        let mut manager = McpManager::default();
+        manager.register_server(
+            make_server_config("s1"),
+            ToolFilter::default(),
+            Box::new(InMemoryMcpClient::default().with_tool("t", json!({"v": 42}))),
+        );
+        let result = manager.call_tool("s1", "t", json!({})).unwrap();
+        assert_eq!(result["v"], 42);
+    }
+
+    #[test]
+    fn manager_call_tool_errors_on_missing_server() {
+        let manager = McpManager::default();
+        let err = manager.call_tool("nope", "t", json!({})).unwrap_err();
+        assert!(err.to_string().contains("not available"));
+    }
+
+    #[test]
+    fn manager_call_qualified_tool_parses_name() {
+        let mut manager = McpManager::default();
+        manager.register_server(
+            make_server_config("my_server"),
+            ToolFilter::default(),
+            Box::new(InMemoryMcpClient::default().with_tool("my_tool", json!({"ok": true}))),
+        );
+        let result = manager
+            .call_qualified_tool("mcp__my_server__my_tool", json!({}))
+            .unwrap();
+        assert_eq!(result["ok"], true);
+    }
+
+    #[test]
+    fn manager_call_qualified_tool_handles_truncated_names() {
+        let long_server = "server".repeat(20);
+        let long_tool = "tool".repeat(20);
+        let mut manager = McpManager::default();
+        manager.register_server(
+            make_server_config(&long_server),
+            ToolFilter::default(),
+            Box::new(InMemoryMcpClient::default().with_tool(&long_tool, json!({"ok": true}))),
+        );
+        let tools = manager.list_tools().unwrap();
+        let qualified = &tools[0].qualified_name;
+        assert!(qualified.len() <= 64);
+        assert!(parse_qualified_tool_name(qualified).is_ok());
+
+        let result = manager.call_qualified_tool(qualified, json!({})).unwrap();
+        assert_eq!(result["ok"], true);
+    }
+
+    #[test]
+    fn manager_unregister_removes_server() {
+        let mut manager = McpManager::default();
+        manager.register_server(
+            make_server_config("s1"),
+            ToolFilter::default(),
+            Box::new(InMemoryMcpClient::default()),
+        );
+        manager.unregister_server("s1").unwrap();
+        assert!(manager.configs.is_empty());
+    }
+
+    #[test]
+    fn manager_unregister_errors_on_unknown() {
+        let mut manager = McpManager::default();
+        let err = manager.unregister_server("nope").unwrap_err();
+        assert!(err.to_string().contains("not registered"));
+    }
+
+    #[test]
+    fn manager_stop_server_errors_on_unknown() {
+        let mut manager = McpManager::default();
+        let err = manager.stop_server("nope").unwrap_err();
+        assert!(err.to_string().contains("not running"));
+    }
+
+    #[test]
+    fn manager_list_resources_returns_from_clients() {
+        let mut manager = McpManager::default();
+        manager.register_server(
+            make_server_config("s1"),
+            ToolFilter::default(),
+            Box::new(
+                InMemoryMcpClient::default().with_resource("mcp://s1/health", json!({"ok": true})),
+            ),
+        );
+        let resources = manager.list_resources().unwrap();
+        assert_eq!(resources.len(), 1);
+        assert_eq!(resources[0].server_name, "s1");
+    }
+
+    #[test]
+    fn manager_read_resource_delegates() {
+        let mut manager = McpManager::default();
+        manager.register_server(
+            make_server_config("s1"),
+            ToolFilter::default(),
+            Box::new(
+                InMemoryMcpClient::default().with_resource("mcp://s1/health", json!({"ok": true})),
+            ),
+        );
+        let result = manager.read_resource("s1", "mcp://s1/health").unwrap();
+        assert_eq!(result["ok"], true);
+    }
+
+    #[test]
+    fn manager_update_sandbox_state_returns_notices() {
+        let mut manager = McpManager::default();
+        manager.register_server(
+            make_server_config("s1"),
+            ToolFilter::default(),
+            Box::new(InMemoryMcpClient::default()),
+        );
+        let notices = manager.update_sandbox_state("strict", "/tmp").unwrap();
+        assert_eq!(notices.len(), 1);
+        assert_eq!(notices[0]["server_name"], "s1");
+    }
+
+    // ── Tool filter ────────────────────────────────────────────────────
+
+    #[test]
+    fn allowed_by_filter_empty_allow_permits_all() {
+        let filter = ToolFilter {
+            allow: vec![],
+            deny: vec![],
+        };
+        assert!(allowed_by_filter("anything", &filter));
+    }
+
+    #[test]
+    fn allowed_by_filter_deny_blocks() {
+        let filter = ToolFilter {
+            allow: vec![],
+            deny: vec!["danger".to_string()],
+        };
+        assert!(!allowed_by_filter("danger", &filter));
+        assert!(allowed_by_filter("safe", &filter));
+    }
+
+    #[test]
+    fn allowed_by_filter_allow_only_permits_listed() {
+        let filter = ToolFilter {
+            allow: vec!["a".to_string()],
+            deny: vec![],
+        };
+        assert!(allowed_by_filter("a", &filter));
+        assert!(!allowed_by_filter("b", &filter));
+    }
+
+    // ── Helper functions ───────────────────────────────────────────────
+
+    #[test]
+    fn sanitize_component_lowercases_and_replaces_specials() {
+        assert_eq!(sanitize_component("My-Server.Name"), "my_server_name");
+        assert_eq!(sanitize_component("ABC123"), "abc123");
+    }
+
+    #[test]
+    fn qualify_tool_name_produces_mcp_prefix() {
+        let name = qualify_tool_name("server", "tool");
+        assert!(name.starts_with("mcp__server__tool"));
+    }
+
+    #[test]
+    fn qualify_tool_name_truncates_long_names() {
+        let long_server = "a".repeat(100);
+        let name = qualify_tool_name(&long_server, "tool");
+        assert!(name.len() <= 64);
+        assert!(parse_qualified_tool_name(&name).is_ok());
+    }
+
+    #[test]
+    fn parse_qualified_tool_name_round_trip() {
+        let qualified = qualify_tool_name("my_server", "my_tool");
+        let (server, tool) = parse_qualified_tool_name(&qualified).unwrap();
+        assert_eq!(server, "my_server");
+        assert_eq!(tool, "my_tool");
+    }
+
+    #[test]
+    fn parse_qualified_tool_name_rejects_missing_prefix() {
+        let err = parse_qualified_tool_name("not_mcp__server__tool").unwrap_err();
+        assert!(err.to_string().contains("missing mcp__ prefix"));
+    }
+
+    #[test]
+    fn parse_qualified_tool_name_rejects_empty_segments() {
+        let err = parse_qualified_tool_name("mcp____tool").unwrap_err();
+        assert!(err.to_string().contains("missing server segment"));
+    }
+
+    #[test]
+    fn parse_server_from_uri_extracts_server() {
+        assert_eq!(
+            parse_server_from_uri("mcp://my-server/capabilities"),
+            Some("my-server".to_string())
+        );
+    }
+
+    #[test]
+    fn parse_server_from_uri_returns_none_for_invalid() {
+        assert!(parse_server_from_uri("http://not-mcp").is_none());
+        assert!(parse_server_from_uri("mcp:///path").is_none());
+    }
+
+    // ── JsonRpcError ───────────────────────────────────────────────────
+
+    #[test]
+    fn jsonrpc_error_codes_are_correct() {
+        assert_eq!(JsonRpcError::parse_error("").code, -32700);
+        assert_eq!(JsonRpcError::invalid_request("").code, -32600);
+        assert_eq!(JsonRpcError::method_not_found("x").code, -32601);
+        assert_eq!(JsonRpcError::invalid_params("").code, -32602);
+        assert_eq!(JsonRpcError::internal("").code, -32603);
+    }
+
+    #[test]
+    fn jsonrpc_result_produces_valid_envelope() {
+        let result = jsonrpc_result(Some(json!(1)), json!({"ok": true}));
+        assert_eq!(result["jsonrpc"], "2.0");
+        assert_eq!(result["id"], 1);
+        assert_eq!(result["result"]["ok"], true);
+    }
+
+    #[test]
+    fn jsonrpc_error_produces_valid_envelope() {
+        let err = jsonrpc_error(Some(json!(2)), JsonRpcError::invalid_params("bad"));
+        assert_eq!(err["jsonrpc"], "2.0");
+        assert_eq!(err["id"], 2);
+        assert_eq!(err["error"]["code"], -32602);
+    }
+
+    // ── McpServerConfig serialization ──────────────────────────────────
+
+    #[test]
+    fn mcp_server_config_defaults_enabled_to_true() {
+        let json = json!({"name": "s", "command": "cmd"});
+        let config: McpServerConfig = serde_json::from_value(json).unwrap();
+        assert!(config.enabled);
+        assert!(config.args.is_empty());
+        assert!(config.env.is_empty());
+    }
+
+    #[test]
+    fn mcp_startup_status_serializes_with_snake_case() {
+        let status = McpStartupStatus::Failed {
+            error: "oops".to_string(),
+        };
+        let json = serde_json::to_value(&status).unwrap();
+        assert_eq!(json["failed"]["error"], "oops");
+    }
+}