Removing remaining CDP generic

Follow up to https://github.com/lightpanda-io/browser/pull/1990 which makes both BrowserContext and Command non-generic.
2026-03-30 17:18:57 +00:00 · 2026-03-30 13:04:14 +08:00
parent 8eeeeda8c1
commit 0a04eabc57
19 changed files with 642 additions and 621 deletions
--- a/src/cdp/CDP.zig
+++ b/src/cdp/CDP.zig
--- a/src/cdp/domains/accessibility.zig
+++ b/src/cdp/domains/accessibility.zig
@@ -18,8 +18,9 @@

 const std = @import("std");
 const id = @import("../id.zig");
+const CDP = @import("../CDP.zig");

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        enable,
        disable,
@@ -32,15 +33,15 @@ pub fn processMessage(cmd: anytype) !void {
        .getFullAXTree => return getFullAXTree(cmd),
    }
 }
-fn enable(cmd: anytype) !void {
+fn enable(cmd: *CDP.Command) !void {
    return cmd.sendResult(null, .{});
 }

-fn disable(cmd: anytype) !void {
+fn disable(cmd: *CDP.Command) !void {
    return cmd.sendResult(null, .{});
 }

-fn getFullAXTree(cmd: anytype) !void {
+fn getFullAXTree(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        depth: ?i32 = null,
        frameId: ?[]const u8 = null,
--- a/src/cdp/domains/browser.zig
+++ b/src/cdp/domains/browser.zig
@@ -17,6 +17,7 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

 const std = @import("std");
+const CDP = @import("../CDP.zig");

 // TODO: hard coded data
 const PROTOCOL_VERSION = "1.3";
@@ -35,7 +36,7 @@ const PRODUCT = "Chrome/124.0.6367.29";
 const JS_VERSION = "12.4.254.8";
 const DEV_TOOLS_WINDOW_ID = 1923710101;

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        getVersion,
        setPermission,
@@ -57,7 +58,7 @@ pub fn processMessage(cmd: anytype) !void {
    }
 }

-fn getVersion(cmd: anytype) !void {
+fn getVersion(cmd: *CDP.Command) !void {
    // TODO: pre-serialize?
    return cmd.sendResult(.{
        .protocolVersion = PROTOCOL_VERSION,
@@ -69,7 +70,7 @@ fn getVersion(cmd: anytype) !void {
 }

 // TODO: noop method
-fn setDownloadBehavior(cmd: anytype) !void {
+fn setDownloadBehavior(cmd: *CDP.Command) !void {
    // const params = (try cmd.params(struct {
    //     behavior: []const u8,
    //     browserContextId: ?[]const u8 = null,
@@ -80,7 +81,7 @@ fn setDownloadBehavior(cmd: anytype) !void {
    return cmd.sendResult(null, .{ .include_session_id = false });
 }

-fn getWindowForTarget(cmd: anytype) !void {
+fn getWindowForTarget(cmd: *CDP.Command) !void {
    // const params = (try cmd.params(struct {
    //     targetId: ?[]const u8 = null,
    // })) orelse return error.InvalidParams;
@@ -91,22 +92,22 @@ fn getWindowForTarget(cmd: anytype) !void {
 }

 // TODO: noop method
-fn setWindowBounds(cmd: anytype) !void {
+fn setWindowBounds(cmd: *CDP.Command) !void {
    return cmd.sendResult(null, .{});
 }

 // TODO: noop method
-fn grantPermissions(cmd: anytype) !void {
+fn grantPermissions(cmd: *CDP.Command) !void {
    return cmd.sendResult(null, .{});
 }

 // TODO: noop method
-fn setPermission(cmd: anytype) !void {
+fn setPermission(cmd: *CDP.Command) !void {
    return cmd.sendResult(null, .{});
 }

 // TODO: noop method
-fn resetPermissions(cmd: anytype) !void {
+fn resetPermissions(cmd: *CDP.Command) !void {
    return cmd.sendResult(null, .{});
 }

--- a/src/cdp/domains/css.zig
+++ b/src/cdp/domains/css.zig
@@ -17,8 +17,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

 const std = @import("std");
+const CDP = @import("../CDP.zig");

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        enable,
    }, cmd.input.action) orelse return error.UnknownMethod;
--- a/src/cdp/domains/dom.zig
+++ b/src/cdp/domains/dom.zig
@@ -18,17 +18,18 @@

 const std = @import("std");
 const id = @import("../id.zig");
-const log = @import("../../log.zig");
+const CDP = @import("../CDP.zig");
 const Node = @import("../Node.zig");
+
+const log = @import("../../log.zig");
+const dump = @import("../../browser/dump.zig");
+const js = @import("../../browser/js/js.zig");
 const DOMNode = @import("../../browser/webapi/Node.zig");
 const Selector = @import("../../browser/webapi/selector/Selector.zig");

-const dump = @import("../../browser/dump.zig");
-const js = @import("../../browser/js/js.zig");
-
 const Allocator = std.mem.Allocator;

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        enable,
        getDocument,
@@ -69,7 +70,7 @@ pub fn processMessage(cmd: anytype) !void {
 }

 // https://chromedevtools.github.io/devtools-protocol/tot/DOM/#method-getDocument
-fn getDocument(cmd: anytype) !void {
+fn getDocument(cmd: *CDP.Command) !void {
    const Params = struct {
        // CDP documentation implies that 0 isn't valid, but it _does_ work in Chrome
        depth: i32 = 3,
@@ -89,7 +90,7 @@ fn getDocument(cmd: anytype) !void {
 }

 // https://chromedevtools.github.io/devtools-protocol/tot/DOM/#method-performSearch
-fn performSearch(cmd: anytype) !void {
+fn performSearch(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        query: []const u8,
        includeUserAgentShadowDOM: ?bool = null,
@@ -116,7 +117,7 @@ fn performSearch(cmd: anytype) !void {
 // hierarchy of each nodes.
 // We dispatch event in the reverse order: from the top level to the direct parents.
 // We should dispatch a node only if it has never been sent.
-fn dispatchSetChildNodes(cmd: anytype, dom_nodes: []const *DOMNode) !void {
+fn dispatchSetChildNodes(cmd: *CDP.Command, dom_nodes: []const *DOMNode) !void {
    const arena = cmd.arena;
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
    const session_id = bc.session_id orelse return error.SessionIdNotLoaded;
@@ -172,7 +173,7 @@ fn dispatchSetChildNodes(cmd: anytype, dom_nodes: []const *DOMNode) !void {
 }

 // https://chromedevtools.github.io/devtools-protocol/tot/DOM/#method-discardSearchResults
-fn discardSearchResults(cmd: anytype) !void {
+fn discardSearchResults(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        searchId: []const u8,
    })) orelse return error.InvalidParams;
@@ -184,7 +185,7 @@ fn discardSearchResults(cmd: anytype) !void {
 }

 // https://chromedevtools.github.io/devtools-protocol/tot/DOM/#method-getSearchResults
-fn getSearchResults(cmd: anytype) !void {
+fn getSearchResults(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        searchId: []const u8,
        fromIndex: u32,
@@ -209,7 +210,7 @@ fn getSearchResults(cmd: anytype) !void {
    return cmd.sendResult(.{ .nodeIds = node_ids[params.fromIndex..params.toIndex] }, .{});
 }

-fn querySelector(cmd: anytype) !void {
+fn querySelector(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        nodeId: Node.Id,
        selector: []const u8,
@@ -235,7 +236,7 @@ fn querySelector(cmd: anytype) !void {
    }, .{});
 }

-fn querySelectorAll(cmd: anytype) !void {
+fn querySelectorAll(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        nodeId: Node.Id,
        selector: []const u8,
@@ -266,7 +267,7 @@ fn querySelectorAll(cmd: anytype) !void {
    }, .{});
 }

-fn resolveNode(cmd: anytype) !void {
+fn resolveNode(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        nodeId: ?Node.Id = null,
        backendNodeId: ?u32 = null,
@@ -327,7 +328,7 @@ fn resolveNode(cmd: anytype) !void {
    } }, .{});
 }

-fn describeNode(cmd: anytype) !void {
+fn describeNode(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        nodeId: ?Node.Id = null,
        backendNodeId: ?Node.Id = null,
@@ -374,7 +375,7 @@ fn rectToQuad(rect: DOMNode.Element.DOMRect) Quad {
    };
 }

-fn scrollIntoViewIfNeeded(cmd: anytype) !void {
+fn scrollIntoViewIfNeeded(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        nodeId: ?Node.Id = null,
        backendNodeId: ?u32 = null,
@@ -397,7 +398,7 @@ fn scrollIntoViewIfNeeded(cmd: anytype) !void {
    return cmd.sendResult(null, .{});
 }

-fn getNode(arena: Allocator, bc: anytype, node_id: ?Node.Id, backend_node_id: ?Node.Id, object_id: ?[]const u8) !*Node {
+fn getNode(arena: Allocator, bc: *CDP.BrowserContext, node_id: ?Node.Id, backend_node_id: ?Node.Id, object_id: ?[]const u8) !*Node {
    const input_node_id = node_id orelse backend_node_id;
    if (input_node_id) |input_node_id_| {
        return bc.node_registry.lookup_by_id.get(input_node_id_) orelse return error.NodeNotFound;
@@ -417,7 +418,7 @@ fn getNode(arena: Allocator, bc: anytype, node_id: ?Node.Id, backend_node_id: ?N

 // https://chromedevtools.github.io/devtools-protocol/tot/DOM/#method-getContentQuads
 // Related to: https://drafts.csswg.org/cssom-view/#the-geometryutils-interface
-fn getContentQuads(cmd: anytype) !void {
+fn getContentQuads(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        nodeId: ?Node.Id = null,
        backendNodeId: ?Node.Id = null,
@@ -443,7 +444,7 @@ fn getContentQuads(cmd: anytype) !void {
    return cmd.sendResult(.{ .quads = &.{quad} }, .{});
 }

-fn getBoxModel(cmd: anytype) !void {
+fn getBoxModel(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        nodeId: ?Node.Id = null,
        backendNodeId: ?u32 = null,
@@ -472,7 +473,7 @@ fn getBoxModel(cmd: anytype) !void {
    } }, .{});
 }

-fn requestChildNodes(cmd: anytype) !void {
+fn requestChildNodes(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        nodeId: Node.Id,
        depth: i32 = 1,
@@ -496,7 +497,7 @@ fn requestChildNodes(cmd: anytype) !void {
    return cmd.sendResult(null, .{});
 }

-fn getFrameOwner(cmd: anytype) !void {
+fn getFrameOwner(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        frameId: []const u8,
    })) orelse return error.InvalidParams;
@@ -512,7 +513,7 @@ fn getFrameOwner(cmd: anytype) !void {
    return cmd.sendResult(.{ .nodeId = node.id, .backendNodeId = node.id }, .{});
 }

-fn getOuterHTML(cmd: anytype) !void {
+fn getOuterHTML(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        nodeId: ?Node.Id = null,
        backendNodeId: ?Node.Id = null,
@@ -534,7 +535,7 @@ fn getOuterHTML(cmd: anytype) !void {
    return cmd.sendResult(.{ .outerHTML = aw.written() }, .{});
 }

-fn requestNode(cmd: anytype) !void {
+fn requestNode(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        objectId: []const u8,
    })) orelse return error.InvalidParams;
--- a/src/cdp/domains/emulation.zig
+++ b/src/cdp/domains/emulation.zig
@@ -17,9 +17,10 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

 const std = @import("std");
+const CDP = @import("../CDP.zig");
 const log = @import("../../log.zig");

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        setEmulatedMedia,
        setFocusEmulationEnabled,
@@ -38,7 +39,7 @@ pub fn processMessage(cmd: anytype) !void {
 }

 // TODO: noop method
-fn setEmulatedMedia(cmd: anytype) !void {
+fn setEmulatedMedia(cmd: *CDP.Command) !void {
    // const input = (try const incoming.params(struct {
    //     media: ?[]const u8 = null,
    //     features: ?[]struct{
@@ -51,7 +52,7 @@ fn setEmulatedMedia(cmd: anytype) !void {
 }

 // TODO: noop method
-fn setFocusEmulationEnabled(cmd: anytype) !void {
+fn setFocusEmulationEnabled(cmd: *CDP.Command) !void {
    // const input = (try const incoming.params(struct {
    //     enabled: bool,
    // })) orelse return error.InvalidParams;
@@ -59,16 +60,16 @@ fn setFocusEmulationEnabled(cmd: anytype) !void {
 }

 // TODO: noop method
-fn setDeviceMetricsOverride(cmd: anytype) !void {
+fn setDeviceMetricsOverride(cmd: *CDP.Command) !void {
    return cmd.sendResult(null, .{});
 }

 // TODO: noop method
-fn setTouchEmulationEnabled(cmd: anytype) !void {
+fn setTouchEmulationEnabled(cmd: *CDP.Command) !void {
    return cmd.sendResult(null, .{});
 }

-fn setUserAgentOverride(cmd: anytype) !void {
+fn setUserAgentOverride(cmd: *CDP.Command) !void {
    log.info(.app, "setUserAgentOverride ignored", .{});
    return cmd.sendResult(null, .{});
 }
--- a/src/cdp/domains/fetch.zig
+++ b/src/cdp/domains/fetch.zig
@@ -17,17 +17,19 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

 const std = @import("std");
-const Allocator = std.mem.Allocator;

 const id = @import("../id.zig");
+const CDP = @import("../CDP.zig");
 const log = @import("../../log.zig");
-const network = @import("network.zig");

 const HttpClient = @import("../../browser/HttpClient.zig");
 const net_http = @import("../../network/http.zig");
 const Notification = @import("../../Notification.zig");

-pub fn processMessage(cmd: anytype) !void {
+const network = @import("network.zig");
+const Allocator = std.mem.Allocator;
+
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        disable,
        enable,
@@ -135,13 +137,13 @@ const ErrorReason = enum {
    BlockedByResponse,
 };

-fn disable(cmd: anytype) !void {
+fn disable(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
    bc.fetchDisable();
    return cmd.sendResult(null, .{});
 }

-fn enable(cmd: anytype) !void {
+fn enable(cmd: *CDP.Command) !void {
    const params = (try cmd.params(EnableParam)) orelse EnableParam{};
    if (!arePatternsSupported(params.patterns)) {
        log.warn(.not_implemented, "Fetch.enable", .{ .params = "pattern" });
@@ -180,7 +182,7 @@ fn arePatternsSupported(patterns: []RequestPattern) bool {
    return true;
 }

-pub fn requestIntercept(bc: anytype, intercept: *const Notification.RequestIntercept) !void {
+pub fn requestIntercept(bc: *CDP.BrowserContext, intercept: *const Notification.RequestIntercept) !void {
    // detachTarget could be called, in which case, we still have a page doing
    // things, but no session.
    const session_id = bc.session_id orelse return;
@@ -215,7 +217,7 @@ pub fn requestIntercept(bc: anytype, intercept: *const Notification.RequestInter
    intercept.wait_for_interception.* = true;
 }

-fn continueRequest(cmd: anytype) !void {
+fn continueRequest(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
    const params = (try cmd.params(struct {
        requestId: []const u8, // INT-{d}"
@@ -275,7 +277,7 @@ const AuthChallengeResponse = enum {
    ProvideCredentials,
 };

-fn continueWithAuth(cmd: anytype) !void {
+fn continueWithAuth(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
    const params = (try cmd.params(struct {
        requestId: []const u8, // "INT-{d}"
@@ -318,7 +320,7 @@ fn continueWithAuth(cmd: anytype) !void {
    return cmd.sendResult(null, .{});
 }

-fn fulfillRequest(cmd: anytype) !void {
+fn fulfillRequest(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;

    const params = (try cmd.params(struct {
@@ -360,7 +362,7 @@ fn fulfillRequest(cmd: anytype) !void {
    return cmd.sendResult(null, .{});
 }

-fn failRequest(cmd: anytype) !void {
+fn failRequest(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
    const params = (try cmd.params(struct {
        requestId: []const u8, // "INT-{d}"
@@ -382,7 +384,7 @@ fn failRequest(cmd: anytype) !void {
    return cmd.sendResult(null, .{});
 }

-pub fn requestAuthRequired(bc: anytype, intercept: *const Notification.RequestAuthRequired) !void {
+pub fn requestAuthRequired(bc: *CDP.BrowserContext, intercept: *const Notification.RequestAuthRequired) !void {
    // detachTarget could be called, in which case, we still have a page doing
    // things, but no session.
    const session_id = bc.session_id orelse return;
--- a/src/cdp/domains/input.zig
+++ b/src/cdp/domains/input.zig
@@ -17,8 +17,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

 const std = @import("std");
+const CDP = @import("../CDP.zig");

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        dispatchKeyEvent,
        dispatchMouseEvent,
@@ -33,7 +34,7 @@ pub fn processMessage(cmd: anytype) !void {
 }

 // https://chromedevtools.github.io/devtools-protocol/tot/Input/#method-dispatchKeyEvent
-fn dispatchKeyEvent(cmd: anytype) !void {
+fn dispatchKeyEvent(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        type: Type,
        key: []const u8 = "",
@@ -74,7 +75,7 @@ fn dispatchKeyEvent(cmd: anytype) !void {
 }

 // https://chromedevtools.github.io/devtools-protocol/tot/Input/#method-dispatchMouseEvent
-fn dispatchMouseEvent(cmd: anytype) !void {
+fn dispatchMouseEvent(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        x: f64,
        y: f64,
@@ -104,7 +105,7 @@ fn dispatchMouseEvent(cmd: anytype) !void {
 }

 // https://chromedevtools.github.io/devtools-protocol/tot/Input/#method-insertText
-fn insertText(cmd: anytype) !void {
+fn insertText(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        text: []const u8, // The text to insert
    })) orelse return error.InvalidParams;
--- a/src/cdp/domains/inspector.zig
+++ b/src/cdp/domains/inspector.zig
@@ -17,8 +17,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

 const std = @import("std");
+const CDP = @import("../CDP.zig");

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        enable,
        disable,
--- a/src/cdp/domains/log.zig
+++ b/src/cdp/domains/log.zig
@@ -17,8 +17,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

 const std = @import("std");
+const CDP = @import("../CDP.zig");

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        enable,
        disable,
--- a/src/cdp/domains/lp.zig
+++ b/src/cdp/domains/lp.zig
@@ -18,14 +18,18 @@

 const std = @import("std");
 const lp = @import("lightpanda");
+
+const CDP = @import("../CDP.zig");
+const Node = @import("../Node.zig");
+
+const DOMNode = @import("../../browser/webapi/Node.zig");
+
 const markdown = lp.markdown;
 const SemanticTree = lp.SemanticTree;
 const interactive = lp.interactive;
 const structured_data = lp.structured_data;
-const Node = @import("../Node.zig");
-const DOMNode = @import("../../browser/webapi/Node.zig");

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        getMarkdown,
        getSemanticTree,
@@ -51,7 +55,7 @@ pub fn processMessage(cmd: anytype) !void {
    }
 }

-fn getSemanticTree(cmd: anytype) !void {
+fn getSemanticTree(cmd: *CDP.Command) !void {
    const Params = struct {
        format: ?enum { text } = null,
        prune: ?bool = null,
@@ -96,7 +100,7 @@ fn getSemanticTree(cmd: anytype) !void {
    }, .{});
 }

-fn getMarkdown(cmd: anytype) !void {
+fn getMarkdown(cmd: *CDP.Command) !void {
    const Params = struct {
        nodeId: ?Node.Id = null,
    };
@@ -119,7 +123,7 @@ fn getMarkdown(cmd: anytype) !void {
    }, .{});
 }

-fn getInteractiveElements(cmd: anytype) !void {
+fn getInteractiveElements(cmd: *CDP.Command) !void {
    const Params = struct {
        nodeId: ?Node.Id = null,
    };
@@ -141,7 +145,7 @@ fn getInteractiveElements(cmd: anytype) !void {
    }, .{});
 }

-fn getStructuredData(cmd: anytype) !void {
+fn getStructuredData(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.NoBrowserContext;
    const page = bc.session.currentPage() orelse return error.PageNotLoaded;

@@ -156,7 +160,7 @@ fn getStructuredData(cmd: anytype) !void {
    }, .{});
 }

-fn detectForms(cmd: anytype) !void {
+fn detectForms(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.NoBrowserContext;
    const page = bc.session.currentPage() orelse return error.PageNotLoaded;

@@ -173,7 +177,7 @@ fn detectForms(cmd: anytype) !void {
    }, .{});
 }

-fn clickNode(cmd: anytype) !void {
+fn clickNode(cmd: *CDP.Command) !void {
    const Params = struct {
        nodeId: ?Node.Id = null,
        backendNodeId: ?Node.Id = null,
@@ -194,7 +198,7 @@ fn clickNode(cmd: anytype) !void {
    return cmd.sendResult(.{}, .{});
 }

-fn fillNode(cmd: anytype) !void {
+fn fillNode(cmd: *CDP.Command) !void {
    const Params = struct {
        nodeId: ?Node.Id = null,
        backendNodeId: ?Node.Id = null,
@@ -216,7 +220,7 @@ fn fillNode(cmd: anytype) !void {
    return cmd.sendResult(.{}, .{});
 }

-fn scrollNode(cmd: anytype) !void {
+fn scrollNode(cmd: *CDP.Command) !void {
    const Params = struct {
        nodeId: ?Node.Id = null,
        backendNodeId: ?Node.Id = null,
@@ -244,7 +248,7 @@ fn scrollNode(cmd: anytype) !void {
    return cmd.sendResult(.{}, .{});
 }

-fn waitForSelector(cmd: anytype) !void {
+fn waitForSelector(cmd: *CDP.Command) !void {
    const Params = struct {
        selector: []const u8,
        timeout: ?u32 = null,
--- a/src/cdp/domains/network.zig
+++ b/src/cdp/domains/network.zig
@@ -18,18 +18,21 @@

 const std = @import("std");
 const lp = @import("lightpanda");
-const Allocator = std.mem.Allocator;
+
 const log = @import("../../log.zig");

-const CdpStorage = @import("storage.zig");
-
 const id = @import("../id.zig");
+const CDP = @import("../CDP.zig");
+
 const URL = @import("../../browser/URL.zig");
 const Transfer = @import("../../browser/HttpClient.zig").Transfer;
 const Notification = @import("../../Notification.zig");
 const Mime = @import("../../browser/Mime.zig");

-pub fn processMessage(cmd: anytype) !void {
+const CdpStorage = @import("storage.zig");
+const Allocator = std.mem.Allocator;
+
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        enable,
        disable,
@@ -59,19 +62,19 @@ pub fn processMessage(cmd: anytype) !void {
    }
 }

-fn enable(cmd: anytype) !void {
+fn enable(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
    try bc.networkEnable();
    return cmd.sendResult(null, .{});
 }

-fn disable(cmd: anytype) !void {
+fn disable(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
    bc.networkDisable();
    return cmd.sendResult(null, .{});
 }

-fn setExtraHTTPHeaders(cmd: anytype) !void {
+fn setExtraHTTPHeaders(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        headers: std.json.ArrayHashMap([]const u8),
    })) orelse return error.InvalidParams;
@@ -110,7 +113,7 @@ fn cookieMatches(cookie: *const Cookie, name: []const u8, domain: ?[]const u8, p
    return true;
 }

-fn deleteCookies(cmd: anytype) !void {
+fn deleteCookies(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        name: []const u8,
        url: ?[:0]const u8 = null,
@@ -144,14 +147,14 @@ fn deleteCookies(cmd: anytype) !void {
    return cmd.sendResult(null, .{});
 }

-fn clearBrowserCookies(cmd: anytype) !void {
+fn clearBrowserCookies(cmd: *CDP.Command) !void {
    if (try cmd.params(struct {}) != null) return error.InvalidParams;
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
    bc.session.cookie_jar.clearRetainingCapacity();
    return cmd.sendResult(null, .{});
 }

-fn setCookie(cmd: anytype) !void {
+fn setCookie(cmd: *CDP.Command) !void {
    const params = (try cmd.params(
        CdpStorage.CdpCookie,
    )) orelse return error.InvalidParams;
@@ -162,7 +165,7 @@ fn setCookie(cmd: anytype) !void {
    try cmd.sendResult(.{ .success = true }, .{});
 }

-fn setCookies(cmd: anytype) !void {
+fn setCookies(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        cookies: []const CdpStorage.CdpCookie,
    })) orelse return error.InvalidParams;
@@ -178,7 +181,7 @@ fn setCookies(cmd: anytype) !void {
 const GetCookiesParam = struct {
    urls: ?[]const [:0]const u8 = null,
 };
-fn getCookies(cmd: anytype) !void {
+fn getCookies(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
    const params = (try cmd.params(GetCookiesParam)) orelse GetCookiesParam{};

@@ -201,7 +204,7 @@ fn getCookies(cmd: anytype) !void {
    try cmd.sendResult(.{ .cookies = writer }, .{});
 }

-fn getResponseBody(cmd: anytype) !void {
+fn getResponseBody(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        requestId: []const u8, // "REQ-{d}"
    })) orelse return error.InvalidParams;
@@ -227,7 +230,7 @@ fn getResponseBody(cmd: anytype) !void {
    }, .{});
 }

-pub fn httpRequestFail(bc: anytype, msg: *const Notification.RequestFail) !void {
+pub fn httpRequestFail(bc: *CDP.BrowserContext, msg: *const Notification.RequestFail) !void {
    // It's possible that the request failed because we aborted when the client
    // sent Target.closeTarget. In that case, bc.session_id will be cleared
    // already, and we can skip sending these messages to the client.
@@ -247,7 +250,7 @@ pub fn httpRequestFail(bc: anytype, msg: *const Notification.RequestFail) !void
    }, .{ .session_id = session_id });
 }

-pub fn httpRequestStart(bc: anytype, msg: *const Notification.RequestStart) !void {
+pub fn httpRequestStart(bc: *CDP.BrowserContext, msg: *const Notification.RequestStart) !void {
    // detachTarget could be called, in which case, we still have a page doing
    // things, but no session.
    const session_id = bc.session_id orelse return;
@@ -276,7 +279,7 @@ pub fn httpRequestStart(bc: anytype, msg: *const Notification.RequestStart) !voi
    }, .{ .session_id = session_id });
 }

-pub fn httpResponseHeaderDone(arena: Allocator, bc: anytype, msg: *const Notification.ResponseHeaderDone) !void {
+pub fn httpResponseHeaderDone(arena: Allocator, bc: *CDP.BrowserContext, msg: *const Notification.ResponseHeaderDone) !void {
    // detachTarget could be called, in which case, we still have a page doing
    // things, but no session.
    const session_id = bc.session_id orelse return;
@@ -293,7 +296,7 @@ pub fn httpResponseHeaderDone(arena: Allocator, bc: anytype, msg: *const Notific
    }, .{ .session_id = session_id });
 }

-pub fn httpRequestDone(bc: anytype, msg: *const Notification.RequestDone) !void {
+pub fn httpRequestDone(bc: *CDP.BrowserContext, msg: *const Notification.RequestDone) !void {
    // detachTarget could be called, in which case, we still have a page doing
    // things, but no session.
    const session_id = bc.session_id orelse return;
--- a/src/cdp/domains/page.zig
+++ b/src/cdp/domains/page.zig
@@ -1,4 +1,5 @@
 // Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+
 //
 // Francis Bouvier <francis@lightpanda.io>
 // Pierre Tachoire <pierre@lightpanda.io>
@@ -22,6 +23,8 @@ const lp = @import("lightpanda");
 const screenshot_png = @embedFile("screenshot.png");

 const id = @import("../id.zig");
+const CDP = @import("../CDP.zig");
+
 const log = @import("../../log.zig");
 const js = @import("../../browser/js/js.zig");
 const URL = @import("../../browser/URL.zig");
@@ -31,7 +34,7 @@ const Notification = @import("../../Notification.zig");

 const Allocator = std.mem.Allocator;

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        enable,
        getFrameTree,
@@ -78,7 +81,7 @@ const Frame = struct {
    gatedAPIFeatures: [][]const u8 = &[0][]const u8{},
 };

-fn getFrameTree(cmd: anytype) !void {
+fn getFrameTree(cmd: *CDP.Command) !void {
    // Stagehand parses the response and error if we don't return a
    // correct one for this call when browser context or target id are missing.
    const startup = .{
@@ -108,7 +111,7 @@ fn getFrameTree(cmd: anytype) !void {
    }, .{});
 }

-fn setLifecycleEventsEnabled(cmd: anytype) !void {
+fn setLifecycleEventsEnabled(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        enabled: bool,
    })) orelse return error.InvalidParams;
@@ -149,7 +152,7 @@ fn setLifecycleEventsEnabled(cmd: anytype) !void {
    return cmd.sendResult(null, .{});
 }

-fn addScriptToEvaluateOnNewDocument(cmd: anytype) !void {
+fn addScriptToEvaluateOnNewDocument(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        source: []const u8,
        worldName: ?[]const u8 = null,
@@ -179,7 +182,7 @@ fn addScriptToEvaluateOnNewDocument(cmd: anytype) !void {
    }, .{});
 }

-fn removeScriptToEvaluateOnNewDocument(cmd: anytype) !void {
+fn removeScriptToEvaluateOnNewDocument(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        identifier: []const u8,
    })) orelse return error.InvalidParams;
@@ -198,7 +201,7 @@ fn removeScriptToEvaluateOnNewDocument(cmd: anytype) !void {
    return cmd.sendResult(null, .{});
 }

-fn close(cmd: anytype) !void {
+fn close(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;

    const target_id = bc.target_id orelse return error.TargetNotLoaded;
@@ -235,7 +238,7 @@ fn close(cmd: anytype) !void {
    bc.target_id = null;
 }

-fn createIsolatedWorld(cmd: anytype) !void {
+fn createIsolatedWorld(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        frameId: []const u8,
        worldName: []const u8,
@@ -255,7 +258,7 @@ fn createIsolatedWorld(cmd: anytype) !void {
    return cmd.sendResult(.{ .executionContextId = js_context.id }, .{});
 }

-fn navigate(cmd: anytype) !void {
+fn navigate(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        url: [:0]const u8,
        // referrer: ?[]const u8 = null,
@@ -289,7 +292,7 @@ fn navigate(cmd: anytype) !void {
    });
 }

-fn doReload(cmd: anytype) !void {
+fn doReload(cmd: *CDP.Command) !void {
    const params = try cmd.params(struct {
        ignoreCache: ?bool = null,
        scriptToEvaluateOnLoad: ?[]const u8 = null,
@@ -319,7 +322,7 @@ fn doReload(cmd: anytype) !void {
    });
 }

-pub fn pageNavigate(bc: anytype, event: *const Notification.PageNavigate) !void {
+pub fn pageNavigate(bc: *CDP.BrowserContext, event: *const Notification.PageNavigate) !void {
    // detachTarget could be called, in which case, we still have a page doing
    // things, but no session.
    const session_id = bc.session_id orelse return;
@@ -371,7 +374,7 @@ pub fn pageNavigate(bc: anytype, event: *const Notification.PageNavigate) !void
    }, .{ .session_id = session_id });
 }

-pub fn pageRemove(bc: anytype) !void {
+pub fn pageRemove(bc: *CDP.BrowserContext) !void {
    // Clear all remote object mappings to prevent stale objectIds from being used
    // after the context is destroy
    bc.inspector_session.inspector.resetContextGroup();
@@ -382,7 +385,7 @@ pub fn pageRemove(bc: anytype) !void {
    }
 }

-pub fn pageCreated(bc: anytype, page: *Page) !void {
+pub fn pageCreated(bc: *CDP.BrowserContext, page: *Page) !void {
    _ = bc.cdp.page_arena.reset(.{ .retain_with_limit = 1024 * 512 });

    for (bc.isolated_worlds.items) |isolated_world| {
@@ -394,7 +397,7 @@ pub fn pageCreated(bc: anytype, page: *Page) !void {
    bc.captured_responses = .empty;
 }

-pub fn pageFrameCreated(bc: anytype, event: *const Notification.PageFrameCreated) !void {
+pub fn pageFrameCreated(bc: *CDP.BrowserContext, event: *const Notification.PageFrameCreated) !void {
    const session_id = bc.session_id orelse return;

    const cdp = bc.cdp;
@@ -415,7 +418,7 @@ pub fn pageFrameCreated(bc: anytype, event: *const Notification.PageFrameCreated
    }
 }

-pub fn pageNavigated(arena: Allocator, bc: anytype, event: *const Notification.PageNavigated) !void {
+pub fn pageNavigated(arena: Allocator, bc: *CDP.BrowserContext, event: *const Notification.PageNavigated) !void {
    // detachTarget could be called, in which case, we still have a page doing
    // things, but no session.
    const session_id = bc.session_id orelse return;
@@ -597,15 +600,15 @@ pub fn pageNavigated(arena: Allocator, bc: anytype, event: *const Notification.P
    }, .{ .session_id = session_id });
 }

-pub fn pageNetworkIdle(bc: anytype, event: *const Notification.PageNetworkIdle) !void {
+pub fn pageNetworkIdle(bc: *CDP.BrowserContext, event: *const Notification.PageNetworkIdle) !void {
    return sendPageLifecycle(bc, "networkIdle", event.timestamp, &id.toFrameId(event.frame_id), &id.toLoaderId(event.req_id));
 }

-pub fn pageNetworkAlmostIdle(bc: anytype, event: *const Notification.PageNetworkAlmostIdle) !void {
+pub fn pageNetworkAlmostIdle(bc: *CDP.BrowserContext, event: *const Notification.PageNetworkAlmostIdle) !void {
    return sendPageLifecycle(bc, "networkAlmostIdle", event.timestamp, &id.toFrameId(event.frame_id), &id.toLoaderId(event.req_id));
 }

-fn sendPageLifecycle(bc: anytype, name: []const u8, timestamp: u64, frame_id: []const u8, loader_id: []const u8) !void {
+fn sendPageLifecycle(bc: *CDP.BrowserContext, name: []const u8, timestamp: u64, frame_id: []const u8, loader_id: []const u8) !void {
    // detachTarget could be called, in which case, we still have a page doing
    // things, but no session.
    const session_id = bc.session_id orelse return;
@@ -640,7 +643,7 @@ fn base64Encode(comptime input: []const u8) [std.base64.standard.Encoder.calcSiz
    return buf;
 }

-fn captureScreenshot(cmd: anytype) !void {
+fn captureScreenshot(cmd: *CDP.Command) !void {
    const Params = struct {
        format: ?[]const u8 = "png",
        quality: ?u8 = null,
@@ -676,7 +679,7 @@ fn captureScreenshot(cmd: anytype) !void {
    }, .{});
 }

-fn getLayoutMetrics(cmd: anytype) !void {
+fn getLayoutMetrics(cmd: *CDP.Command) !void {
    const width = 1920;
    const height = 1080;

--- a/src/cdp/domains/performance.zig
+++ b/src/cdp/domains/performance.zig
@@ -17,8 +17,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

 const std = @import("std");
+const CDP = @import("../CDP.zig");

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        enable,
        disable,
--- a/src/cdp/domains/runtime.zig
+++ b/src/cdp/domains/runtime.zig
@@ -19,7 +19,9 @@
 const std = @import("std");
 const builtin = @import("builtin");

-pub fn processMessage(cmd: anytype) !void {
+const CDP = @import("../CDP.zig");
+
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        enable,
        runIfWaitingForDebugger,
@@ -36,7 +38,7 @@ pub fn processMessage(cmd: anytype) !void {
    }
 }

-fn sendInspector(cmd: anytype, action: anytype) !void {
+fn sendInspector(cmd: *CDP.Command, action: anytype) !void {
    // save script in file at debug mode
    if (builtin.mode == .Debug) {
        try logInspector(cmd, action);
@@ -48,7 +50,7 @@ fn sendInspector(cmd: anytype, action: anytype) !void {
    bc.callInspector(cmd.input.json);
 }

-fn logInspector(cmd: anytype, action: anytype) !void {
+fn logInspector(cmd: *CDP.Command, action: anytype) !void {
    const script = switch (action) {
        .evaluate => blk: {
            const params = (try cmd.params(struct {
--- a/src/cdp/domains/security.zig
+++ b/src/cdp/domains/security.zig
@@ -17,8 +17,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

 const std = @import("std");
+const CDP = @import("../CDP.zig");

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        enable,
        disable,
@@ -32,7 +33,7 @@ pub fn processMessage(cmd: anytype) !void {
    }
 }

-fn setIgnoreCertificateErrors(cmd: anytype) !void {
+fn setIgnoreCertificateErrors(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        ignore: bool,
    })) orelse return error.InvalidParams;
--- a/src/cdp/domains/storage.zig
+++ b/src/cdp/domains/storage.zig
@@ -18,13 +18,16 @@

 const std = @import("std");

+const CDP = @import("../CDP.zig");
+
 const log = @import("../../log.zig");
 const URL = @import("../../browser/URL.zig");
 const Cookie = @import("../../browser/webapi/storage/storage.zig").Cookie;
+
 const CookieJar = Cookie.Jar;
 pub const PreparedUri = Cookie.PreparedUri;

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        clearCookies,
        setCookies,
@@ -40,7 +43,7 @@ pub fn processMessage(cmd: anytype) !void {

 const BrowserContextParam = struct { browserContextId: ?[]const u8 = null };

-fn clearCookies(cmd: anytype) !void {
+fn clearCookies(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
    const params = (try cmd.params(BrowserContextParam)) orelse BrowserContextParam{};

@@ -55,7 +58,7 @@ fn clearCookies(cmd: anytype) !void {
    return cmd.sendResult(null, .{});
 }

-fn getCookies(cmd: anytype) !void {
+fn getCookies(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
    const params = (try cmd.params(BrowserContextParam)) orelse BrowserContextParam{};

@@ -69,7 +72,7 @@ fn getCookies(cmd: anytype) !void {
    try cmd.sendResult(.{ .cookies = writer }, .{});
 }

-fn setCookies(cmd: anytype) !void {
+fn setCookies(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;
    const params = (try cmd.params(struct {
        cookies: []const CdpCookie,
--- a/src/cdp/domains/target.zig
+++ b/src/cdp/domains/target.zig
@@ -20,11 +20,13 @@ const std = @import("std");
 const lp = @import("lightpanda");

 const id = @import("../id.zig");
+const CDP = @import("../CDP.zig");
+
 const log = @import("../../log.zig");
 const URL = @import("../../browser/URL.zig");
 const js = @import("../../browser/js/js.zig");

-pub fn processMessage(cmd: anytype) !void {
+pub fn processMessage(cmd: *CDP.Command) !void {
    const action = std.meta.stringToEnum(enum {
        getTargets,
        attachToTarget,
@@ -60,7 +62,7 @@ pub fn processMessage(cmd: anytype) !void {
    }
 }

-fn getTargets(cmd: anytype) !void {
+fn getTargets(cmd: *CDP.Command) !void {
    // If no context available, return an empty array.
    const bc = cmd.browser_context orelse {
        return cmd.sendResult(.{
@@ -86,7 +88,7 @@ fn getTargets(cmd: anytype) !void {
    }, .{ .include_session_id = false });
 }

-fn getBrowserContexts(cmd: anytype) !void {
+fn getBrowserContexts(cmd: *CDP.Command) !void {
    var browser_context_ids: []const []const u8 = undefined;
    if (cmd.browser_context) |bc| {
        browser_context_ids = &.{bc.id};
@@ -99,7 +101,7 @@ fn getBrowserContexts(cmd: anytype) !void {
    }, .{ .include_session_id = false });
 }

-fn createBrowserContext(cmd: anytype) !void {
+fn createBrowserContext(cmd: *CDP.Command) !void {
    const params = try cmd.params(struct {
        disposeOnDetach: bool = false,
        proxyServer: ?[:0]const u8 = null,
@@ -130,7 +132,7 @@ fn createBrowserContext(cmd: anytype) !void {
    }, .{});
 }

-fn disposeBrowserContext(cmd: anytype) !void {
+fn disposeBrowserContext(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        browserContextId: []const u8,
    })) orelse return error.InvalidParams;
@@ -141,7 +143,7 @@ fn disposeBrowserContext(cmd: anytype) !void {
    try cmd.sendResult(null, .{});
 }

-fn createTarget(cmd: anytype) !void {
+fn createTarget(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        url: [:0]const u8 = "about:blank",
        // width: ?u64 = null,
@@ -230,7 +232,7 @@ fn createTarget(cmd: anytype) !void {
    }, .{});
 }

-fn attachToTarget(cmd: anytype) !void {
+fn attachToTarget(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        targetId: []const u8,
        flatten: bool = true,
@@ -247,7 +249,7 @@ fn attachToTarget(cmd: anytype) !void {
    return cmd.sendResult(.{ .sessionId = bc.session_id }, .{});
 }

-fn attachToBrowserTarget(cmd: anytype) !void {
+fn attachToBrowserTarget(cmd: *CDP.Command) !void {
    const bc = cmd.browser_context orelse return error.BrowserContextNotLoaded;

    const session_id = bc.session_id orelse cmd.cdp.session_id_gen.next();
@@ -269,7 +271,7 @@ fn attachToBrowserTarget(cmd: anytype) !void {
    return cmd.sendResult(.{ .sessionId = bc.session_id }, .{});
 }

-fn closeTarget(cmd: anytype) !void {
+fn closeTarget(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        targetId: []const u8,
    })) orelse return error.InvalidParams;
@@ -310,7 +312,7 @@ fn closeTarget(cmd: anytype) !void {
    bc.target_id = null;
 }

-fn getTargetInfo(cmd: anytype) !void {
+fn getTargetInfo(cmd: *CDP.Command) !void {
    const Params = struct {
        targetId: ?[]const u8 = null,
    };
@@ -347,7 +349,7 @@ fn getTargetInfo(cmd: anytype) !void {
    }, .{ .include_session_id = false });
 }

-fn sendMessageToTarget(cmd: anytype) !void {
+fn sendMessageToTarget(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        message: []const u8,
        sessionId: []const u8,
@@ -365,32 +367,19 @@ fn sendMessageToTarget(cmd: anytype) !void {
        return error.UnknownSessionId;
    }

-    const Capture = struct {
-        aw: std.Io.Writer.Allocating,
-
-        pub fn sendJSON(self: *@This(), message: anytype) !void {
-            return std.json.Stringify.value(message, .{
-                .emit_null_optional_fields = false,
-            }, &self.aw.writer);
-        }
-    };
-
-    var capture = Capture{
-        .aw = .init(cmd.arena),
-    };
-
-    cmd.cdp.dispatch(cmd.arena, &capture, params.message) catch |err| {
+    var aw = std.Io.Writer.Allocating.init(cmd.arena);
+    cmd.cdp.dispatch(cmd.arena, .{ .capture = &aw.writer }, params.message) catch |err| {
        log.err(.cdp, "internal dispatch error", .{ .err = err, .id = cmd.input.id, .message = params.message });
        return err;
    };

    try cmd.sendEvent("Target.receivedMessageFromTarget", .{
-        .message = capture.aw.written(),
+        .message = aw.written(),
        .sessionId = params.sessionId,
    }, .{});
 }

-fn detachFromTarget(cmd: anytype) !void {
+fn detachFromTarget(cmd: *CDP.Command) !void {
    if (cmd.browser_context) |bc| {
        if (bc.session_id) |session_id| {
            try cmd.sendEvent("Target.detachedFromTarget", .{
@@ -404,11 +393,11 @@ fn detachFromTarget(cmd: anytype) !void {
 }

 // TODO: noop method
-fn setDiscoverTargets(cmd: anytype) !void {
+fn setDiscoverTargets(cmd: *CDP.Command) !void {
    return cmd.sendResult(null, .{});
 }

-fn setAutoAttach(cmd: anytype) !void {
+fn setAutoAttach(cmd: *CDP.Command) !void {
    const params = (try cmd.params(struct {
        autoAttach: bool,
        waitForDebuggerOnStart: bool,
@@ -468,7 +457,7 @@ fn setAutoAttach(cmd: anytype) !void {
    try cmd.sendResult(null, .{});
 }

-fn doAttachtoTarget(cmd: anytype, target_id: []const u8) !void {
+fn doAttachtoTarget(cmd: *CDP.Command, target_id: []const u8) !void {
    const bc = cmd.browser_context.?;
    const session_id = bc.session_id orelse cmd.cdp.session_id_gen.next();

--- a/src/cdp/testing.zig
+++ b/src/cdp/testing.zig
@@ -64,7 +64,7 @@ const TestContext = struct {
        session_id: ?[]const u8 = null,
        url: ?[:0]const u8 = null,
    };
-    pub fn loadBrowserContext(self: *TestContext, opts: BrowserContextOpts) !*CDP.BrowserContext(CDP) {
+    pub fn loadBrowserContext(self: *TestContext, opts: BrowserContextOpts) !*CDP.BrowserContext {
        var c = self.cdp();
        if (c.browser_context) |bc| {
            _ = c.disposeBrowserContext(bc.id);