find-ccsplayer-movementservices-checkjumpbutton-waterpatch

name	find-CCSPlayer_MovementServices_CheckJumpButton_WaterPatch
description	Find and patch the water jump velocity inside CCSPlayer_MovementServices_CheckJumpButton in CS2 binary using IDA Pro MCP. This patch changes the water jump velocity from 100.0f to 145.0f by modifying the immediate operand of a mov instruction. Use this skill when reverse engineering CS2 server.dll or libserver.so to locate and patch the water jump height value. Trigger: water jump patch, CheckJumpButton water velocity, jump height patch, water jump 145
disable-model-invocation	true

CCSPlayer_MovementServices_CheckJumpButton_WaterPatch

Overview

Locate the water jump velocity assignment inside CCSPlayer_MovementServices_CheckJumpButton and generate a patch that changes the immediate value from 100.0f (0x42C80000) to 145.0f (0x43110000).

The target code pattern in pseudocode:

if ( v5 == (int *)0x8000 )    // move type check for water
{
    *(_DWORD *)(a2 + 64) = 1120403456;  // <-- patch target: 100.0f -> 145.0f
}

In assembly, this is a mov dword ptr [reg+40h], 42C80000h instruction. The patch changes the immediate operand from 42C80000h (100.0f) to 43110000h (145.0f).

Prerequisites

• CCSPlayer_MovementServices_CheckJumpButton must already be identified. Use SKILL /get-func-from-yaml with func_name=CCSPlayer_MovementServices_CheckJumpButton to load its address. If YAML does not exist, run SKILL /find-CCSPlayer_MovementServices_CheckJumpButton first.

Location Steps

1. Get CheckJumpButton Function Address

ALWAYS Use SKILL /get-func-from-yaml with func_name=CCSPlayer_MovementServices_CheckJumpButton.

If the skill returns an error, stop and report to user.

2. Decompile and Locate the Water Jump Pattern

Decompile the function:

mcp__ida-pro-mcp__decompile(addr="<func_va>")

In the decompiled output, search for the water jump velocity pattern. The key indicators are:

• A comparison against 0x8000 (water move type)
• Inside the if-block: *(_DWORD *)(a2 + 64) = 1120403456 (which is 100.0f as IEEE 754)
• Note: 1120403456 decimal = 0x42C80000 = 100.0f in IEEE 754 floating point

Note the address annotation on the assignment line.

3. Disassemble Around the Assignment

Disassemble the function around the annotated address to find the exact mov instruction:

mcp__ida-pro-mcp__disasm(addr="<func_va>", offset=<estimated_offset>, max_instructions=20)

Look for this assembly pattern:

cmp     rax, 8000h              ; check water move type
jnz     short loc_XXXXXXXX      ; skip if not water
mov     dword ptr [rsi+40h], 42C80000h  ; <-- patch target: 100.0f

Record:

• patch_va: Address of the mov dword ptr [reg+40h], 42C80000h instruction

4. Determine Patch Bytes

Read the original bytes of the mov instruction:

mcp__ida-pro-mcp__get_bytes(regions={"addr": "<patch_va>", "size": 7})

The original 7-byte instruction: C7 46 40 00 00 C8 42

• C7 46 40 = opcode + ModR/M for mov dword ptr [rsi+40h]
• 00 00 C8 42 = immediate 0x42C80000 (100.0f, little-endian)

Patch bytes: C7 46 40 00 00 11 43

• Same opcode + ModR/M
• 00 00 11 43 = immediate 0x43110000 (145.0f, little-endian)

5. Generate Patch Signature

ALWAYS Use SKILL /generate-signature-for-patch to generate and validate the signature.

Required context for the skill:

• func_name: CCSPlayer_MovementServices_CheckJumpButton
• func_va: From step 1
• patch_va: Address of the mov instruction from step 3
• original_instruction: mov dword ptr [rsi+40h], 42C80000h
• patched_instruction: mov dword ptr [rsi+40h], 43110000h
• description: Change water jump velocity from 100.0f to 145.0f in CheckJumpButton

6. Write YAML Output

ALWAYS Use SKILL /write-patch-as-yaml to persist the results.

Required parameters:

• patch_name: CCSPlayer_MovementServices_CheckJumpButton_WaterPatch
• patch_sig: The validated signature from step 5
• patch_bytes: C7 46 40 00 00 11 43
• patch_sig_disp: From step 5 result (omit if 0)

IEEE 754 Float Reference

• 100.0f = 0x42C80000 = 1120403456 decimal
• 145.0f = 0x43110000 = 1125122048 decimal

Output YAML Files

• CCSPlayer_MovementServices_CheckJumpButton_WaterPatch.windows.yaml
• CCSPlayer_MovementServices_CheckJumpButton_WaterPatch.linux.yaml