[Dignity]

Just wrote this for you. It has been tested but has no code to prevent abuse.

Usage:
- Jump onto a ledge; then press jump again to get put into movement mode.
- Move your character using "Y" (negative x) and "N" (positive x).
- Press jump again to get released from the ledge.

Things to consider:
- You should add a way to figure out when a object ends, so the player can't freely move around the map
- You should add an alternate function to allow players to climb on top / over of ledges.

pawn Код:

new bool: p_ClimbingLedge[MAX_PLAYERS char];

public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
    new Float: pX, Float: pY, Float: pZ;
    GetPlayerPos(playerid, pX, pY, pZ);

    if(newkeys & KEY_JUMP)
    {
        if(IsPlayerClimbingLedge(playerid))
        {
            if(p_ClimbingLedge{playerid})
            {
                TogglePlayerControllable(playerid, true);
                p_ClimbingLedge{playerid} = false;
                
                return true;
            }
        
            TogglePlayerControllable(playerid, false);
            p_ClimbingLedge{playerid} = true;
            
            ApplyAnimation(playerid, "PED", "CLIMB_idle", 4.1, 0, 1, 1, 1, 0, 1);
        }
    }

    if(newkeys & KEY_YES)
    {
        if(IsPlayerClimbingLedge(playerid) && p_ClimbingLedge{playerid})
        {
            SetPlayerPos(playerid, pX - 1, pY, pZ);
            ApplyAnimation(playerid, "PED", "CLIMB_idle", 4.1, 0, 1, 1, 1, 0, 1);
        }
    }
    
    if(newkeys & KEY_NO)
    {
        if(IsPlayerClimbingLedge(playerid) && p_ClimbingLedge{playerid})
        {
            SetPlayerPos(playerid, pX + 1, pY, pZ);
            ApplyAnimation(playerid, "PED", "CLIMB_idle", 4.1, 0, 1, 1, 1, 0, 1);
        }
    }

    return true;
}

IsPlayerClimbingLedge(playerid)
{
    new const animlist[][] = {
        {"CLIMB_idle"},
        {"CLIMB_jump"},
        {"CLIMB_jump_B"},
        {"CLIMB_Pull"}
    };

    static animlib[32], animname[32];

    GetAnimationName(GetPlayerAnimationIndex(playerid), animlib, sizeof(animlib), animname, sizeof(animname));
    
    for(new i; i < sizeof(animlist); i ++)
    {
        if(strcmp(animname, animlist[i][0], true) == 0)
        {
            return true;
        }
    }
    
    return false;
}

Here's a preview of what it looks like: https://www.youtube.com/watch?v=iXKXTrVlggU