find-csource2client-ondisconnect

name	find-CSource2Client_OnDisconnect
description	Find and identify the CSource2Client_OnDisconnect function in CS2 binary using IDA Pro MCP. Use this skill when reverse engineering CS2 client.dll or libclient.so to locate the OnDisconnect function by searching for the "client_disconnect" and "reason_code" debug strings and analyzing cross-references to find the matching code pattern.
disable-model-invocation	true

Find CSource2Client_OnDisconnect

Locate CSource2Client_OnDisconnect in CS2 client.dll or libclient.so using IDA Pro MCP tools.

Method

1. Search for the Debug Strings

mcp__ida-pro-mcp__find_regex pattern="client_disconnect"
mcp__ida-pro-mcp__find_regex pattern="reason_code"

2. Get Cross-References to Both Strings

mcp__ida-pro-mcp__xrefs_to addrs="<client_disconnect_string_addr>"
mcp__ida-pro-mcp__xrefs_to addrs="<reason_code_string_addr>"

3. Identify the Target Function

Find the function that has cross-references to BOTH "client_disconnect" and "reason_code" strings. This is CSource2Client_OnDisconnect.

Decompile the candidate function and verify it matches this code pattern:

__int64 __fastcall CSource2Client_OnDisconnect(__int64 a1, unsigned int a2)
{
  // ...
  if ( (*(unsigned int (__fastcall **)(__int64, const char *))(*(_QWORD *)qword_XXXXXXXX + 104LL))(
         qword_XXXXXXXX,
         "client_disconnect") != -1 )
  {
    v3 = (*(__int64 (__fastcall **)(__int64, const char *, _QWORD, _QWORD))(*(_QWORD *)qword_XXXXXXXX + 48LL))(
           qword_XXXXXXXX,
           "client_disconnect",
           0LL,
           0LL);
    // ...
    LODWORD(v11) = sub_XXXXXXXX("reason_code", 11LL, ...);
    // ...
  }
  // ...
}

Identification criteria:

• The function references both "client_disconnect" and "reason_code" strings
• It takes two parameters: (this_ptr, reason_code_value) where reason_code_value is an unsigned int
• "client_disconnect" is used to check and create a game event
• "reason_code" is used as a key name to set the reason code field on the event

4. Rename the Function

mcp__ida-pro-mcp__rename batch={"func": [{"addr": "<function_addr>", "name": "CSource2Client_OnDisconnect"}]}

5. Generate Signature

ALWAYS Use SKILL /generate-signature-for-function to generate a robust and unique signature for the function.

6. Write IDA Analysis Output as YAML

ALWAYS Use SKILL /write-func-as-yaml to write the analysis results.

Required parameters:

• func_name: CSource2Client_OnDisconnect
• func_addr: The function address from step 3
• func_sig: The validated signature from step 5

Function Characteristics

• Type: Non-virtual (regular) function
• Parameters: (this_ptr, reason_code) — this_ptr is the CSource2Client instance, reason_code is an unsigned int disconnect reason
• Purpose: Handles client disconnect by firing a "client_disconnect" game event with the given reason code

Output YAML Format

The output YAML filename depends on the platform:

• client.dll → CSource2Client_OnDisconnect.windows.yaml
• libclient.so → CSource2Client_OnDisconnect.linux.yaml