CodeFizz Editor Agent vs Rekall MCP Tools for Unreal Engine

Find what makes the game slow

You ask: "Why does this level drop to 40 frames a second?"

The agent records an Unreal Insights trace while the game runs, then reads it for you. It names the worst frames, the functions that cost the most time and the GPU passes that take the longest. It can also switch one console variable on and off and report the difference in frame time, GPU passes and CPU timers.

Needs Unreal Engine 5.7 or 5.8.

Commands: performance_start_trace, performance_analyze_insight, performance_profile_gpu, performance_ab

Debug a Blueprint step by step

You ask: "Why does the door not open when I press E?"

The agent puts a breakpoint on a node and starts the game. When play stops at that node, it reads the call stack and the values on the object, then steps forward one node at a time. It can also watch a pin and list the nodes that ran last. This is the Blueprint debugger you already know, with the agent at the controls.

Commands: set_breakpoint, debug_step, get_call_stack, inspect_debug_value, set_pin_watch

Look inside a running Niagara effect

You ask: "Why do no particles show, and why is this effect so expensive?"

The agent reads the live particle count and the values on each particle, the same data the Attribute Spreadsheet shows. It can pause, step or slow down every effect, and it measures what one system costs on the game thread, the render thread and the GPU. If the stack has errors, it reads them and can apply the fix that the Fix issue button in the editor applies.

Commands: get_niagara_particle_stats, get_niagara_particle_data, set_niagara_debug_playback, profile_niagara_system, fix_niagara_stack_issue

See why an AI character does what it does

You ask: "Why is the enemy standing still?"

During play, the agent reads the Behavior Trees that are running and can pause the game when a tree reaches a node you name. It runs an Environment Query and returns the engine's own debug view of the result. On Unreal Engine 5.8 it also reads live Mass entities and the values they hold.

Commands: get_bt_runtime, set_bt_breakpoint, run_env_query, get_mass_entity

Test a rig before an animator touches it

You ask: "Does the cloak cut through the body when the character runs?"

The agent runs the rig for as many frames as you ask, with no window open. It reports limbs that cross, feet that go through the ground, bones that shake, and how deep one mesh goes into another. It also tells you how long the rig takes to solve and which nodes cost the most.

Commands: simulate_rig, measure_mesh_penetration, get_rig_motion_report, profile_rig

Read and explain what is already in the project

You ask: "What does this material do, and what does it cost?"

The agent reads the graph and follows a wire from any node to where it ends. It reports the shader cost numbers that the engine itself shows. For PCG it reads the data that comes out of a single node. It can take a screenshot of the viewport or of an editor window, so you and the agent look at the same picture.

Commands: trace_material_connection, material_stats, pcg_inspect_node_output, take_screenshot